Medical Cannabis for Pulmonary Fibrosis: What Studies Show
Short answer · 2 minute read
People living with pulmonary fibrosis ask about medical cannabis for good reason: the illness is slow, tiring and short on options. In mice and rats, lab-made cannabinoids that switch on the CB2 receptor, or block CB1, reduced lung scarring. No study has tested cannabis in people with pulmonary fibrosis yet, and anything inhaled lands on the very organ that is already damaged.
Every study described on this page was done in lab animals or cells, and each one is labeled that way. The full review starts at what the research shows.
How this guide treats the evidence
- Research figures link to the paper they came from, listed at the end of the page.
- Each result names what it was tested on: mice, rats or cells. Nothing from an animal is passed off as a result in patients.
- Findings that contradict each other stay in, including those that cut against cannabis.
- Reviewed by physicians licensed in the states where we work. See who they are.
Breathless on the stairs, a cough that won’t quit: what pulmonary fibrosis takes from daily life
It often starts small. The stairs to the bedroom need a pause halfway. A dry cough hangs on after a cold that ended weeks ago. Then the walk from the parking lot gets longer, conversations come in short phrases, and a pulse oximeter on the kitchen counter becomes part of the routine.
The diagnosis brings a word that is hard to shake: progressive. Many people spend the first months reading everything they can find, looking for anything that might ease a single symptom.
Short of breath
Scarred lung tissue is stiff and passes oxygen into the blood less easily, so effort that used to be routine now leaves you winded. Carrying groceries, showering and talking while walking are common sticking points.
A dry cough
The cough of pulmonary fibrosis brings up little or nothing. It can come in fits, interrupt meals and calls, and leave the chest and ribs sore.
Tired days, broken nights
Low oxygen, coughing at night and worry about what comes next wear people down. Fatigue and weight loss are listed among the symptoms for a reason.
So why cannabis? Partly because people with a lung disease hear about it for sleep, appetite and anxiety, and partly because headlines report that cannabinoids “reversed lung scarring.” Those headlines describe mice. The sections below separate what was seen in animals from what is known in people, and explain why the way cannabis is taken matters more here than with almost any other diagnosis.
Newly diagnosed, already using cannabis, or someone close to you on oxygen: where to start
Tap the situation that sounds most like yours. The card points to the parts of this guide written for it.
You were diagnosed recently
Begin with the disease itself: which type you have, what usually drives it and what treatment can slow. Cannabis questions make more sense once that picture is clear.
Types of pulmonary fibrosis · How fast it progresses · Treatment today
You already smoke or vape cannabis
With scarred lungs, the form matters as much as the plant. Smoke and vapor reach the damaged tissue directly; other forms avoid that and keep other risks.
You use home oxygen or are being assessed for a transplant
Two hard limits apply here: no flame near oxygen, and transplant centers usually ask about any cannabis use before listing. Read these before anything else.
Who should not use cannabis · Cannabis and a transplant evaluation
Someone close to you has pulmonary fibrosis
Many readers here are a partner or an adult child. The parts on prognosis, the late stage and the conversation with doctors are written with you in mind.
Your state may not list pulmonary fibrosis
Few programs name it word for word. Many cover it through a broader category or leave room for the physician’s judgment.
What is pulmonary fibrosis? Definition, types and is it rare
Pulmonary fibrosis is a condition in which the tissue deep in the lungs becomes scarred over time [1]. The scar forms in the thin walls around the alveoli, the tiny air sacs where oxygen passes into the blood. As those walls thicken and stiffen, breathing takes more work and less oxygen reaches the body [2]. The scarring itself does not heal; treatment aims to slow it and to ease what it causes.
“Pulmonary fibrosis” is a description, not one single disease. It is the end point of several different processes, and the type matters because treatment differs.
Types of pulmonary fibrosis
Idiopathic pulmonary fibrosis (IPF)
“Idiopathic” means no cause can be found, and in most cases none is [1]. IPF is a long-term disease that usually worsens over time [2]. It is diagnosed most often in people in their 60s and 70s and is more common in men [3]. Most cannabinoid research on lung scarring uses IPF as its target.
Other interstitial lung diseases
Interstitial lung disease (ILD) is the family name for conditions that inflame or scar the lung tissue. Scarring can follow connective tissue diseases such as rheumatoid arthritis or scleroderma, inhaled dusts and pollutants, or certain medicines [1]. Finding and removing the trigger is part of treatment.
Progressive pulmonary fibrosis
Lung specialists use this name when a scarring disease other than IPF keeps getting worse despite treatment of its cause. It matters because people in this group may be offered the same antifibrotic medicines used for IPF.
Genetic forms
Pulmonary fibrosis can run in families. Changes in more than 10 genes have been linked to higher risk, including MUC5B, TERT and TERC [3]. A rare inherited condition, Hermansky-Pudlak syndrome, causes its own lung fibrosis; one of the cannabinoid drug candidates below is being developed for it [4].
Is pulmonary fibrosis rare?
It is uncommon, and most people have never heard of it until they or a relative are diagnosed. Because it is mainly a disease of later life, it is often mistaken at first for being out of shape, for asthma or for the aftermath of a chest infection. That delay is one reason a persistent dry cough with breathlessness deserves a proper lung assessment.
Can pulmonary fibrosis be genetic?
Yes, in some families. A family history of the disease raises the risk, and doctors may offer genetic testing when two or more relatives are affected [3][5]. Most people with pulmonary fibrosis, though, have no affected relatives.
How it differs from cystic fibrosis, COPD and asthma · What causes it
Pulmonary fibrosis vs cystic fibrosis, COPD and asthma
The names sound alike and all four make breathing hard, so they get confused, especially pulmonary fibrosis and cystic fibrosis. They have different causes, start at different ages and are treated with different medicines. For cannabis, that has a practical consequence: research on one of them tells you nothing about the others.
Pick a condition to set it beside pulmonary fibrosis.
| Question | Pulmonary fibrosis | Cystic fibrosis | COPD | Asthma |
|---|---|---|---|---|
| What happens in the lungs | Scar tissue thickens the walls of the air sacs, so oxygen crosses into the blood less easily. | Mucus becomes thick and sticky, blocks the airways and traps germs [6]. | Airways narrow and air sacs break down, so air gets trapped in the lungs. | Airways swell and tighten in episodes that usually ease with treatment. |
| Who gets it | Mostly adults in their 60s and 70s [3]. | People born with it; often found through newborn screening [6]. | Adults, usually after years of smoke or fumes. | Any age, often starting in childhood. |
| Main cause | Often unknown; also dusts, some medicines and connective tissue diseases [1]. | An inherited gene change [6]. | Tobacco smoke above all. | Sensitive airways, often with allergy. |
| Usual treatment | Pirfenidone or nintedanib, oxygen, pulmonary rehabilitation, transplant for some [7]. | Chest physical therapy, nutrition, breathing treatments and medicines, including ones aimed at the faulty CFTR protein [6]. | Inhalers that open the airways, rehabilitation, oxygen when needed. | Daily controller and quick-relief inhalers. |
| Cannabinoid research | Animal and cell studies only, reviewed below. | Not covered here; results for scarring do not carry over. | See COPD and medical cannabis. | See asthma and medical cannabis. |
Does pulmonary fibrosis cause COPD? No. They are separate diseases, although a long-time smoker can develop both at once, and a lung specialist can tell from breathing tests and a CT scan which one is driving the symptoms. Cystic fibrosis does not turn into pulmonary fibrosis either; it is inherited and present from birth [6].
What causes pulmonary fibrosis, and does smoking cause it?
In most people no cause is ever found, which is what idiopathic means [1]. Where a cause is known, it usually belongs to one of a handful of groups: something breathed in, a medicine or treatment, or the body’s own immune system turning on the lungs. Age, male sex and family history raise the risk on their own [3].
Is pulmonary fibrosis caused by smoking?
Smoking is a common risk factor among people who have idiopathic pulmonary fibrosis [3]. It does not explain every case, and people who never smoked get the disease too, but quitting and avoiding secondhand smoke, dust and chemical fumes is standard advice after diagnosis [8]. What about cannabis smoke? None of the studies behind this page looked at it, so there is no evidence here that it causes fibrosis, and none that it is harmless to scarred lungs.
Asbestos and other workplace dust
Environmental and workplace pollutants can trigger lung scarring [1]. Asbestos is the best-known example; silica, coal dust, metal dusts, and molds or bird proteins breathed in over years are others. Tell your lung doctor about every job you have held, because the work history can change the diagnosis.
Medicines, including amiodarone
Certain medicines can scar the lungs [1]. Amiodarone, a heart rhythm drug, is one of them, and researchers use it on purpose to create lung fibrosis in rats. The newest cannabinoid study in this field did exactly that before testing whether a cannabinoid could limit the damage [9]; the numbers from that experiment are below. Never stop a prescribed medicine on your own because of this risk; the prescriber weighs it against what the drug protects you from.
Autoimmune disease
Connective tissue diseases such as rheumatoid arthritis and scleroderma can scar the lungs [1]. Treating the underlying disease is part of treating the fibrosis.
Radiation and cancer drugs
Radiation to the chest and some chemotherapy drugs can leave scarring months or years later. Your oncology records belong in any lung assessment.
After a severe lung infection
Some people are left with scarring after severe pneumonia, including COVID-19. Doctors repeat scans to see whether it settles or keeps progressing.
No cause found
When tests rule out every known trigger, the diagnosis is idiopathic pulmonary fibrosis, the most common single type [1].
Pulmonary fibrosis symptoms, flare-ups and pain
Some people have no symptoms at first; they appear and grow as the scarring spreads [2]. The ones below are the most typical [1][5].
Shortness of breath
First with effort, later with everyday tasks. Often the symptom that sends people to a doctor.
Dry, lasting cough
Brings up little or no mucus and does not clear the way a cold cough does.
Fatigue and weight loss
Tiredness and weight loss without dieting, partly from the extra work of breathing.
Clubbing
Fingertips and toes widen and round, and the nails curve, a change seen in heart and lung disease.
Crackles
High-pitched crackles a doctor hears at the base of the lungs, often compared to pulling apart Velcro.
How is pulmonary fibrosis confirmed?
The key test is a high-resolution chest CT scan, which shows the pattern of scarring. Lung function tests measure how much air the lungs hold and how well oxygen passes into the blood. Blood tests look for autoimmune causes, and sometimes a lung biopsy, a fluid sample from the airways (bronchoalveolar lavage) or genetic testing is needed [5].
Pulmonary fibrosis exacerbation symptoms
An acute exacerbation is a sudden worsening of symptoms over days or weeks [8]. Breathlessness that was stable climbs quickly, oxygen readings drop, and the cough may get worse. Often there is no obvious trigger. Exacerbations can be life threatening and are more common in advanced disease [8], so they are treated in the hospital, not waited out at home.
How long do pulmonary fibrosis flare-ups last?
The worsening itself develops over days to weeks [8]. Recovery is less predictable: some people return close to where they were, others settle at a lower level of lung function. That is why lung teams treat any sudden change as urgent.
Does pulmonary fibrosis cause pain?
The scarring itself is not usually described as painful, but pain is common around it. Joint and muscle pain is listed among the symptoms [1], ribs and chest muscles get sore from coughing fits, and the effort of breathing can tighten the chest. New or severe chest pain is a different matter and needs urgent assessment.
Get care today, not a card
- Breathlessness at rest that is new or quickly getting worse
- Oxygen readings lower than your doctor told you to accept
- Blue or gray lips or fingertips, or new confusion
- Chest pain, or coughing up blood
How fast does pulmonary fibrosis progress, and how long can you live with it?
This is usually the first question after diagnosis, and the honest answer is frustrating: the course of idiopathic pulmonary fibrosis is different for each person and cannot be predicted [8]. What doctors can do is follow your own trend. Repeated lung function tests, oxygen levels at rest and on walking, and how you feel over months show which way things are moving far better than any average.
Three courses lung specialists describe. Tap one to see what it looks like and what doctors watch.
Slow and steady
Breathing tests change little from one visit to the next, and daily life adapts gradually. Many people stay in this pattern for long stretches.
What doctors watch
Lung volume and gas transfer on breathing tests every few months, and oxygen levels when you walk.
Faster decline
Test results fall noticeably between visits, and oxygen is needed sooner. This is the pattern where starting or changing antifibrotic treatment, and an early talk about transplant, matter most.
What doctors watch
How quickly the numbers drop, new needs for oxygen, and whether you could be a transplant candidate.
A sudden flare
An acute exacerbation can interrupt either pattern, with symptoms worsening over days or weeks [8]. It needs hospital care and can leave lung function lower afterward.
What doctors watch
Infection, blood clots and heart problems that can look like a flare, and how much oxygen support you need.
Does pulmonary fibrosis always get worse?
Idiopathic pulmonary fibrosis is a progressive disease, so over time it generally does [2]. Speed is the part that varies. Some other types, especially those with a cause that can be removed or treated, can stabilize.
Is pulmonary fibrosis permanent?
The scar tissue that has formed does not go away, which makes pulmonary fibrosis a long-term, chronic condition rather than an acute one. Treatment works on what is still healthy: slowing new scarring and helping the remaining lung do its job [7].
How long can you live with pulmonary fibrosis?
Survival figures quoted online are averages from older patient groups, and they say little about one person. Age, the type of fibrosis, other illnesses, how fast your tests are changing and whether you take antifibrotic medicine all shift the picture. Your lung specialist, looking at your own test trend, is the person able to give an estimate worth hearing, and it is fine to ask directly.
Is pulmonary fibrosis a death sentence?
It is a serious disease that shortens life for many people, and it deserves to be taken seriously. It is not a matter of waiting, though. Medicines can slow it, oxygen and rehabilitation keep people active, a lung transplant is an option for some [7], and palliative care improves quality of life when symptoms are heavy [8].
How does pulmonary fibrosis affect the heart?
The heart and lungs work as a pair. When scarring lowers the oxygen in the blood, the blood vessels in the lungs tighten and their walls thicken. The right side of the heart, which pumps blood through the lungs, then has to push against higher pressure. Pulmonary hypertension is one of the recognized complications of idiopathic pulmonary fibrosis [2][8].
Pulmonary hypertension
What it is
High blood pressure inside the lung arteries, separate from the blood pressure measured on your arm.
What you may notice
Breathlessness out of step with your lung tests, fainting spells, or chest tightness on effort.
Right heart strain (cor pulmonale)
What it is
The right side of the heart enlarges and weakens from working against the pressure for a long time.
What you may notice
Swelling in the ankles and legs, weight gain from fluid, and more tiredness. An echocardiogram is the usual first check.
Cannabis, CBD and heart failure
None of the cannabinoid studies on pulmonary fibrosis measured anything about the heart, so there is nothing to report here on whether cannabis or CBD helps or harms a strained heart in this disease. If you have pulmonary hypertension or heart failure, bring the question to your cardiologist as well as your lung doctor, and read our separate page on heart failure for what research shows there.
End-stage pulmonary fibrosis: final days and palliative care
If you are reading this for yourself or for someone you love, take it slowly. In the late stage, the lungs can no longer deliver enough oxygen into the blood without support; doctors call this respiratory failure [2]. Oxygen needs rise, short walks become hard, and more of the day is spent resting.
How long does end-stage pulmonary fibrosis last?
There is no reliable clock. Some people live for a long time with high oxygen needs; for others, a flare brings the end on quickly. Because the course is so unpredictable [8], lung teams encourage people to talk about their wishes early, while they have the energy, rather than waiting for a crisis.
What the final days can look like
Breathing becomes faster and shallower, sleep takes up most of the day, and appetite fades. Good palliative care keeps the focus on comfort: easing the feeling of breathlessness, calming fear, and keeping the person where they want to be, at home, in a hospice or in the hospital.
What a palliative care team can do
- Treat the sensation of breathlessness with medicines, fans, positioning and breathing techniques.
- Ease anxiety and panic that come with air hunger.
- Help with sleep, cough and pain.
- Support the family and plan care at home or in a hospice.
- Work alongside your lung team, not instead of it; palliative care can start long before the last weeks [8].
Anxiety and medical cannabis · Insomnia and medical cannabis
How to treat pulmonary fibrosis: can it be cured?
Can pulmonary fibrosis be cured?
No. There is currently no cure [7][1]. For a small group of people, a lung transplant replaces the scarred lungs, but it brings its own lifelong treatment. Everything else on this list aims to slow the scarring, help you breathe and protect the lung you still have.
Filter by what a treatment is for.
Antifibrotic medicines
Pirfenidone or nintedanib can help the lungs keep working and may help prevent a flare [7]. They do not undo scarring, and both need regular blood tests.
Treating the cause
When fibrosis comes from an autoimmune disease or something inhaled, treating that disease or ending the exposure is part of the plan, sometimes with steroids or other immune-calming drugs.
Oxygen therapy
Extra oxygen reduces breathlessness and makes exercise easier [7]. It is prescribed by flow rate, for activity, sleep or all day.
Pulmonary rehabilitation
A supervised program of exercise and breathing techniques, such as pursed-lip breathing and pacing, that helps you do more with the lungs you have [7].
Quitting smoking and irritants
Stopping smoking and avoiding dust, chemicals and secondhand smoke protects what healthy lung remains [8].
Treating acid reflux
Reflux (GERD) is common in pulmonary fibrosis. Antacids may help keep stomach acid from reaching the lungs [7].
Vaccines
A chest infection can trigger a flare, so lung teams usually recommend staying current with flu, pneumonia and COVID-19 shots. Ask which ones you are due for.
Lung transplant
An option for some people with serious disease [7]. Assessment takes time, so the conversation is best started early.
No treatments match this filter.
Which treatment is best for pulmonary fibrosis?
The best plan depends on the type of fibrosis, how fast it is moving and your other health problems, and it is set by a lung specialist. Keep taking what has been prescribed. Nothing on this page, cannabis included, is a reason to stop or skip an antifibrotic medicine.
Is medical cannabis worth raising with your lung doctor?
Thirteen short questions about your diagnosis, your oxygen, your medicines and the symptom that bothers you most. You get a summary of how your answers fit what research shows, and what to take to a physician.
13 questions · about a minute · your answers stay in this browser
Why cannabis comes up in lung fibrosis: CB1, CB2 and the endocannabinoid system
Your body makes its own cannabis-like molecules, called endocannabinoids, and reads them through receptors on cells. Together they form the endocannabinoid system. The two best-known receptors are CB1, found widely in the brain and also in the lungs, and CB2, found mostly on immune cells. THC from the cannabis plant switches on both, more strongly CB1; CBD works differently and barely switches on either.
Scarring in the lungs is driven by inflammation and by fibroblasts, the repair cells that lay down collagen. Because CB1 and CB2 sit on the immune cells and repair cells involved, researchers have tested whether turning one receptor up or the other down changes how much scar forms. All of that testing so far is in animals and cells.
Switching CB2 on
In mice whose lungs were scarred with bleomycin, a drug used to cause fibrosis on purpose, the lab compound JWH133 switched on CB2 and reduced inflammation and collagen [10]. A later study found it stopped fibroblasts from turning into scar-making cells by blocking a chain of signals inside them [11]. A different CB2 activator, YX-2102, eased fibrosis in rats [12].
WIN 55212-2, which acts on both receptors, protected mouse lungs after paraquat poisoning and pushed immune cells called macrophages toward a calming type, an effect that ran through CB2 [13].
Blocking CB1
In mice, macrophages in the air sacs release the body’s own cannabinoid anandamide, which acts on CB1 and pushes these cells toward a scar-promoting state. Blocking CB1 in the lungs with MRI-1867, a drug candidate that also blocks an inflammatory enzyme, reduced fibrosis [14]. A large gene-mapping study in mice had pointed to CB1 blockade as a target [15].
Yet one mouse study found the opposite: switching CB1 on also helped. The CB1 puzzle explains why that matters for THC.
What the research shows, from strongest to weakest
In short: nobody has yet tested cannabis or a cannabinoid in people with pulmonary fibrosis. Every result below comes from mice, rats or cells.
Different kinds of study answer different questions. A randomized trial in patients can show whether something helps. A study that observes patients can show a link. An animal or cell experiment can show a mechanism, and that is the only rung this topic has reached.
| Level | What exists for pulmonary fibrosis | What it can and cannot tell you |
|---|---|---|
| Trials in people | None. | The only kind of study that could show a benefit for patients has not been done. |
| Studies that observe patients | None on cannabis use and the course of this disease. | Nothing yet about whether people who use cannabis do better or worse. |
| Animal and cell work | Mouse and rat models of scarring, plus cell experiments, testing lab-made cannabinoids [10][11][14][9]. | Explains why scientists are interested and which receptors to aim at. Cannot tell you what happens in your lungs. |
How has this research grown over the years?
How to read it: one row per year in which a study cited on this page was published; a longer bar means more studies that year. Every bar is animal or cell work, because no study in patients exists yet.
Show as a table
| Year | Studies | Type |
|---|---|---|
| 2016 | 1 | Animal |
| 2017 | 1 | Animal and cell |
| 2022 | 3 | Animal and cell |
| 2023 | 3 | Animal, cell and drug development |
| 2025 | 1 | Animal |
| 2026 | 1 | Animal |
Browse the studies yourself
Each card is one of the papers this guide cites, in a sentence or two. Filter by what the compound does to the receptors.
A cannabinoid in rats with amiodarone scarring
Rats given the heart drug amiodarone daily for 10 days developed lung fibrosis; adding the synthetic cannabinoid O-2545 at 10 mg/kg a day kept a collagen marker near normal [9].
Blocking CB1 in lung immune cells
MRI-1867 delivered into the lungs at 0.5 mg/kg a day eased bleomycin fibrosis; in aged mice it reversed 3,030 fibrosis-related gene changes [14].
JWH133 and scar-making cells
Daily JWH133 at 2.5 mg/kg for 21 days reduced fibrosis by blocking the signals that turn fibroblasts into scar-making cells [11].
How S-MRI-1867 behaves in the body
Between 21% and 60% of an oral dose reached the blood across species, and a half-life of about 31 hours was predicted in people; very low solubility and over 99% protein binding are hurdles for a usable medicine [4].
Mapping the genes of scarring
Fourteen days after bleomycin, 4,730 genes were switched up and 4,854 down; 1,051 changed the same way as in two groups of people with IPF, and the analysis pointed to CB1 blockade as a target [15].
YX-2102, a new CB2 activator
Picked from a library of 1,600 chemicals, YX-2102 given at 25 mg/kg a day eased bleomycin fibrosis in rats when checked at 21 days [12].
WIN 55212-2 after paraquat poisoning
The compound protected mouse lungs from paraquat injury over 28 days and shifted macrophages toward a calming type through CB2 [13].
ACPA, a CB1 activator
ACPA at 3 mg/kg for 14 days improved survival and reduced collagen in bleomycin-treated mice by blocking TGF-beta signals in fibroblasts [16].
The first JWH133 lung study
Daily JWH133 at 2.5 mg/kg eased bleomycin fibrosis after 21 days and held back fibroblast growth and movement in the dish [10].
Ajulemic acid in the scarring phase
The synthetic cannabinoid, given at 1 or 5 mg/kg, reduced fibrosis when started during the scar-forming phase after bleomycin [17].
No studies of this type are cited here.
Lab compounds vs. what a medical card gets you
Here is the gap most headlines skip. The compounds that eased scarring in animals are made in laboratories, and almost none are available to patients. A medical card gives access to products made from the cannabis plant, built around THC, CBD or a mix of the two. A result for one does not transfer to the other.
JWH133
In the studies
Switches on CB2 about 200 times more strongly than CB1; eased fibrosis in mice [11].
With a medical card
Not sold. A research chemical.
YX-2102
In the studies
A new CB2 activator; eased fibrosis in rats [12].
With a medical card
Not sold. A research chemical.
WIN 55212-2
In the studies
Acts on CB1 and CB2; protected mouse lungs after poisoning [13].
With a medical card
Not sold. A research chemical.
ACPA
In the studies
Switches on CB1; improved survival in mice [16].
With a medical card
Not sold. The authors judged it unsuitable for clinical use.
O-2545
In the studies
A synthetic cannabinoid; limited amiodarone scarring in rats [9].
With a medical card
Not sold. A research chemical.
Ajulemic acid
In the studies
A synthetic cannabinoid; reduced fibrosis in mice [17].
With a medical card
Not sold. Not an approved medicine.
What a medical card gives access to
Plant-based products from licensed state programs, labeled with their THC and CBD content. THC switches CB1 on, which is the opposite of what MRI-1867 does. CBD barely touches either receptor. Neither has been studied in pulmonary fibrosis.
Prescription cannabinoids
Dronabinol, nabilone and the CBD medicine Epidiolex are prescribed by a doctor and filled at a pharmacy, not bought with a card. None is approved for pulmonary fibrosis.
The CB1 puzzle: why some lab results point in opposite directions
If you take one thing from the research, take this. The receptor THC acts on most strongly, CB1, has produced contradictory results in lung scarring, and those two results cannot both be the whole story.
In mice, CB1 on macrophages in the air sacs fed scarring. Blocking it in the lungs with MRI-1867 reduced fibrosis [14], and a gene-mapping study had pointed to the same target [15].
In another mouse study, the CB1 activator ACPA improved survival and reduced collagen after bleomycin by calming fibroblasts [16].
Possible reasons include different cell types, doses, timing and models, and the study authors note that much is still unexplored, including the role of CB1 in fibroblasts and results in female animals. Nobody yet knows which result, if either, reflects a human lung.
How big were the effects in animal studies, and how to read them
Effect sizes in animal studies are easy to misread. They come from small groups of genetically similar animals, given scarring on purpose, and treated on a schedule chosen by the researchers. Read them as proof of concept, not as a forecast for patients.
In the clearest experiment, a cannabinoid kept a collagen marker in rats close to normal despite a drug that scars the lungs. In mice, a CB1 blocker reversed thousands of gene changes linked to fibrosis. These are large effects, in animals, under controlled conditions, and none has been repeated in people.
Doses here describe the experiments. They are not doses for people, and there is no way to convert them into a cannabis product.
Why a mouse model is not the same as IPF
Most of these studies scar mouse lungs with a single dose of bleomycin. That produces an injury followed by fibrosis over a few weeks, while idiopathic pulmonary fibrosis in people creeps forward over years [15]. Several studies used only male animals or short timeframes, and none measured long-term safety [9][16]. A result that holds in a three-week mouse model can still fail in a slow human disease.
Smoking, vaping or edibles with scarred lungs: what each form avoids and what stays
Cannabis is not only smoked. Medical products are also vaped, eaten, swallowed as capsules, held under the tongue, sprayed into the mouth, rubbed on the skin, worn as a patch or, rarely, used as suppositories. For most conditions the choice of form is a matter of convenience. With pulmonary fibrosis it decides whether the product touches the damaged organ at all. Some risks belong to one form, some to every form, and some to sharing a device. None of this recommends a form; that choice belongs in a conversation with a physician.
Which form are you asking about?
The card for every form stays in view; picking a form adds what applies to it.
Smoking: joints, blunts, pipes, bongs
Burning plant matter sends hot smoke, tar and fine particles into airways that are already scarred and inflamed. It can set off coughing fits, and none of the animal studies above involved smoke. How much THC each puff delivers cannot be read off a label.
Vaping and dabbing
Dry-herb vaporizers, oil cartridges, pens and dabbing rigs heat rather than burn, so there is no smoke. The hot aerosol still travels down the same airways into the same scarred tissue. Concentrates used for dabbing (wax, shatter, rosin) are strong enough that a small slip becomes a large dose.
Shared devices
Germs pass on shared joints, pipes and vape mouthpieces. For someone with pulmonary fibrosis, a chest infection is one of the things that can set off a flare.
Any flame near home oxygen
Fire hazard
Oxygen makes things burn faster and hotter. A lighter, a joint or a heating device near an oxygen line, concentrator or tank can start a fire that injures the face and airways. Oxygen suppliers ban smoking in the room for this reason.
Edibles, drinks and capsules
Gummies, chocolates, baked goods, drinks, swallowed oils and capsules never reach the lungs. They take an hour or more to act, last for hours, and pass through the liver before reaching the blood. The common trap is a second serving taken because the first “didn’t work,” which is how many accidental overdoses happen.
Tinctures, oils and mouth sprays
Drops held under the tongue and sprays into the cheek avoid the lungs and are easy to count. Part of each dose is swallowed, so liver processing and slower effects still apply.
Creams, balms and patches
Creams and balms act mainly where they are rubbed in, for sore muscles or joints, and do little elsewhere. Transdermal patches are different: they deliver cannabinoids into the bloodstream, so drowsiness and interactions become the same questions as for anything swallowed.
Suppositories
Rarely used. They bypass the lungs and the stomach, but what reaches the blood acts on the whole body, including the brain.
Prescription capsules and solutions
Dronabinol and nabilone are prescription THC-like medicines, and Epidiolex is prescription CBD. They come with a fixed dose and a pharmacist who checks your other medicines. They are not bought with a medical card, and none is approved for pulmonary fibrosis.
True of every form
- THC in any form can cause drowsiness, dizziness and unsteadiness, which matter more when oxygen levels are already low.
- Sedation from cannabis adds to opioids or sleep medicines prescribed for breathlessness or cough.
- THC and CBD are processed by the liver, which also handles antifibrotic medicines.
- THC and CBD are different: a risk or effect of one does not carry over to the other.
- No driving after use.
- Which form, if any, is a decision for you and a physician who knows your oxygen needs and medicines.
All forms as a table
| Form | What it avoids | What it keeps |
|---|---|---|
| Smoking | Slow onset | Smoke in scarred airways, fire risk near oxygen, shared devices, every effect of THC |
| Vaping and dabbing | Burning plant matter | Hot aerosol in the airways, strong concentrates, heat near oxygen, every effect of THC |
| Edibles and capsules | The lungs, flame, shared devices | Slow onset, the second-serving trap, liver processing, interactions, drowsiness |
| Tinctures and sprays | The lungs, flame, shared devices | Part swallowed, liver processing, interactions, drowsiness |
| Creams and balms | The lungs and most whole-body effects | Skin reactions; little effect beyond the area treated |
| Transdermal patches | The lungs and swallowing | Whole-body effects, interactions, drowsiness |
| Suppositories | The lungs and the stomach | Whole-body effects, interactions |
| Prescription capsules | Unknown product content | Drowsiness, dizziness, interactions; not approved for this disease |
Is cannabis safe with pulmonary fibrosis? Side effects
There is no safety data for people with pulmonary fibrosis: the studies were in animals, and their authors state plainly that safety in humans has not been established [9][14]. What follows are the general effects of cannabis, read against the realities of this disease. Open each one for what it means here.
Drowsiness
THC is sedating, and sedation slows breathing a little. For healthy lungs that hardly matters; when oxygen levels run low, it can. Drowsiness also adds up with opioids and sleep medicines often prescribed for cough or breathlessness.
Dizziness and falls when oxygen is low
THC can cause lightheadedness, especially on standing. Combined with low oxygen during effort and the tubing of an oxygen line underfoot, it raises the chance of a fall.
Coughing and airway irritation
This belongs to smoking and vaping, not to cannabis as such. Smoke and hot aerosol irritate the airways and can trigger coughing fits. Forms that are not inhaled avoid this; see what each form keeps.
Racing heart and anxiety
THC can make the heart beat faster and, in some people, bring on anxiety or panic. With pulmonary hypertension or a strained right heart, that is a question for your cardiologist before anything is tried. Air hunger and anxiety already feed each other; a substance that adds to either deserves caution.
Thinking and driving
THC slows reaction time and judgment. Do not drive or operate machinery after using it, and remember that edibles can still be acting hours later.
Drug interactions: pirfenidone, nintedanib, steroids and opioids for breathlessness
None of the studies on this page tested cannabis together with the medicines used in pulmonary fibrosis; the only interaction they describe is a mechanism, the CB2 receptor carrying the anti-inflammatory effect [13]. So this section lists the medicine groups worth raising and the questions to ask, rather than answers that do not exist yet.
Pick what you take to see the questions for it.
Pirfenidone and nintedanib
Both antifibrotics are monitored with regular liver blood tests, and both are broken down by the liver. THC and CBD use the liver’s drug-processing enzymes too.
- Could cannabis change the level of my antifibrotic, or its side effects on the liver and stomach?
- Should my liver tests be checked more often if I start?
- Does smoking anything affect my antifibrotic dose?
Prednisone and immune-suppressing drugs
When fibrosis comes with an autoimmune disease, steroids and drugs such as mycophenolate or azathioprine may be part of treatment. They lower defenses against infection, and some are also processed by the liver.
- Does CBD or THC interact with my immune medicine?
- Is there extra infection risk from a shared device or an unregulated product?
Opioids and sleep medicines for breathlessness or cough
Low-dose morphine and other opioids are sometimes used to ease air hunger and cough, and sleep medicines for broken nights. Their sedation adds to the sedation from THC, and together they can slow breathing more than either alone.
- Is it safe to combine cannabis with my opioid or sleep medicine at my oxygen level?
- What signs of over-sedation should my family watch for?
Reflux medicines
Antacids and acid-reducing drugs are common in pulmonary fibrosis [7]. Some acid reducers are processed by the same liver enzymes as CBD.
- Should a pharmacist review my reflux medicine before I try a CBD product?
No medicine group matches this filter.
Bring every medicine, supplement and product you use to one appointment, and ask your pharmacist to run an interaction check as well. That review is part of what a physician does at a medical cannabis evaluation.
Who should not use cannabis with pulmonary fibrosis
For some people the answer is “not now,” whatever symptom they hoped to ease. These are hard limits, not preferences.
- Anyone who would smoke or vape near home oxygen, a concentrator or an oxygen tank.
- People in the middle of a flare or with oxygen levels falling at rest: get care first.
- Anyone pregnant or breastfeeding.
- People with a past history of psychosis, or with a heart rhythm problem not yet assessed.
- Anyone thinking of stopping an antifibrotic or other prescribed treatment to “try cannabis instead.”
On a lung transplant list, or being assessed for one?
Transplant centers set their own rules on cannabis and many test for it. Using it without telling the team can delay or end a listing. Ask your transplant coordinator before you use anything, and be open about past use.
What science doesn’t know yet
The unknowns here outweigh the knowns, and the study authors list them themselves.
- Whether any cannabinoid helps people with pulmonary fibrosis. There are no human data [9].
- Whether short animal models predict a slow human disease. The common mouse model is an acute injury followed by fibrosis, not the years-long course of IPF [15].
- Whether results hold in females, since part of the work used only male animals [14].
- Whether treatment matters early or late in the disease, and what other scarring pathways are involved [11].
- How the drug candidates behave in people. Human dosing and long-term toxicity are unknown [12][4].
- Which way CB1 points, and so what THC does to scarring.
- Whether any of it applies to plant products sold under a medical card, which were not tested.
How to read a headline about cannabis and lung scarring
- Look for the animal: “in mice” or “in rats” is usually in the second paragraph, if at all.
- Check the compound: a CB2 activator or CB1 blocker is not THC or CBD.
- Ask what was measured: collagen in a lung sample is not breathing, survival or quality of life in a person.
How to talk to your doctor about cannabis and pulmonary fibrosis
Start with expectations. If cannabis has a place, it is for a symptom around the disease, such as sleep, anxiety or appetite, not for the scarring itself. Everything already prescribed stays in place, and the most useful appointment focuses on one or two symptoms and the full medicine list.
What it may be discussed for
- Nights broken by worry or coughing
- Anxiety that rides along with breathlessness
- Poor appetite and weight loss
- Sore muscles and joints
What it will not do
- Slow or reverse scarring in people (never shown)
- Replace oxygen, rehabilitation or antifibrotics
- Make an inhaled form safe for scarred lungs
What to bring to the appointment
Tap each item once it is ready. Nothing is saved.
Questions for your lung doctor
- Would anything about my oxygen levels or heart make cannabis unsafe for me?
- Could it affect my antifibrotic medicine or my liver tests?
- If I try it, which forms keep away from my lungs, and why THC, CBD or a mix?
- What would tell us within a few weeks whether it helps the symptom, and what means stop?
- Does it change anything for a future transplant assessment?
Telling your doctor what you already use is not a confession. It is the information that keeps the advice safe, and physicians hear it every day.
Is pulmonary fibrosis a qualifying condition for a medical marijuana card?
It depends on how your state writes its list. Few programs name pulmonary fibrosis directly, so qualifying usually comes down to one of three routes. The physician at your evaluation checks your records against the wording your state uses today; no outcome is promised in advance.
Named on the list
A small number of programs list lung diseases or pulmonary fibrosis in so many words. Then the diagnosis in your records is the key document.
Covered by a broader category
More often, states include categories such as a chronic or debilitating condition, severe or chronic pain, or cachexia (wasting). Pulmonary fibrosis and its symptoms can fit there.
Left to the physician
Some programs let a physician certify any condition they judge appropriate. The decision then rests on your history and the physician’s assessment.
Medical cannabis rules by state: legal status, possession limits, taxes and home growing
Each state sets its own legal status, how much a patient may possess, whether patients pay lower taxes, and whether growing at home is allowed. Those rules change as legislatures meet, so we keep them on one page per state rather than copying them here: start at cannabis laws and regulations by state. For every other diagnosis we cover, see all qualifying conditions.
Getting a medical card online: steps, price and renewal
The whole evaluation happens from home, which matters when a trip to a clinic means packing an oxygen tank. How it works in detail is on our medical card page; here is the outline.
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About 5 minutes
Fill in the form
Pick your state, list your diagnoses and medicines, and upload the CT report or clinic letter if you have it.
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About 15 minutes
See a physician licensed in your state
One on one and fully online, with no travel. The start time is agreed with the physician, so leave some slack around it.
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In as little as 15 minutes after the appointment, depending on your state
Receive the recommendation
If the physician decides it is appropriate, the signed document appears in your account.
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On the state’s timeline
Register with your state
States with a patient registry review the recommendation and issue the card themselves.
Who runs the appointment
Across 250 reviews from patients in the states where we are licensed. We do not sort them by score and do not hide the low ones.
- 150,000+patients evaluated – everyone who has been through an appointment with us, in every state where we are licensed
- Since 2017doing only this: online evaluations for medical cannabis programs, and nothing else on the side
Appointments are with physicians licensed in your state; you can read about them on our doctors page. You see the price for your state before paying, any state fee goes to the state, and the medical card FAQ covers refunds if no recommendation is issued. Cards expire on a schedule your state sets, and renewal means a new evaluation; if a card goes missing, here is what to do. To move an appointment, use your appointments page; for anything else, contact support.
Pulmonary fibrosis and medical cannabis: FAQ
Is pulmonary fibrosis bad?
It is a serious, long-term lung disease. The scarring does not heal, and idiopathic pulmonary fibrosis usually worsens over time, but at a speed that differs from person to person. Treatment can slow it and ease symptoms.
Can you survive pulmonary fibrosis?
Many people live with it for years, especially with antifibrotic medicine, oxygen and rehabilitation. It is not curable, apart from a lung transplant for some people. Your lung specialist can give the most useful estimate based on your own test results.
How long does pulmonary fibrosis last?
It is a lifelong condition: the scar tissue stays. What changes is how fast new scarring forms, which treatment aims to slow. Flare-ups, by contrast, develop over days or weeks.
Can CBD help pulmonary fibrosis?
There is no evidence that it does. The animal studies tested lab compounds that act on CB2 or block CB1; CBD barely acts on either, and no study has given CBD to people with pulmonary fibrosis. If CBD is considered for sleep or anxiety, ask a physician to check it against your antifibrotic medicine.
Is vaping safer than smoking with pulmonary fibrosis?
Vaping avoids burning, but the hot aerosol still goes into the same scarred airways, and no study shows it is safe for them. Forms that are swallowed, held under the tongue or used on the skin avoid the lungs altogether, while keeping the effects of THC on drowsiness, the liver and other medicines.
Can I use cannabis on home oxygen?
Never smoke or vape, or use any flame or heating device, near oxygen: it is a serious fire risk. Whether a non-inhaled form is reasonable depends on your oxygen levels and medicines, so it is a question for your lung doctor and an evaluating physician.
Will cannabis affect my lung transplant evaluation?
It can. Transplant centers set their own policies, and many test for cannabis and ask candidates to stop. Talk to your transplant coordinator before using anything, and be open about past use.
Is an online medical cannabis evaluation legal?
Yes, in states whose law allows telemedicine for these evaluations. The physician holds a license in your state and decides at the appointment whether a recommendation is appropriate. Details are on our medical card page.
Does my medical card work in another state?
Only where that state accepts out-of-state cards, and the rules vary. Check which states accept out-of-state medical cards before you travel.
What if I lose my medical card?
The state program that issued it replaces it, usually through its online portal. Steps for a lost medical card walks through it; your signed recommendation stays in your account.
More research on cannabis and pulmonary fibrosis
This page cites a selection of studies. Our research library holds every study we track on cannabis and pulmonary fibrosis, from laboratory work to clinical trials, and lets you filter them by cannabinoid, study type and year.
- studies
- 42
- in people
- 17
- clinical trials
- 0
Talk to a licensed physician about pulmonary fibrosis and cannabis
What may be worth discussing: help with sleep, anxiety or appetite for some people, in a form that keeps away from the lungs, under a physician’s eye.
What cannabis cannot do: treat the scarring, slow it in people, or stand in for oxygen and antifibrotic medicine. Keep your current treatment unless your lung specialist changes it.
Your state’s price is on screen before you pay, and the physician alone decides whether a recommendation is right for you.
Share your experience
References
17 sources
- 1. MedlinePlus, National Library of Medicine. Pulmonary Fibrosis. Accessed November 2026.
- 2. National Heart, Lung, and Blood Institute. What Is Idiopathic Pulmonary Fibrosis? Accessed November 2026.
- 3. National Heart, Lung, and Blood Institute. Pulmonary Fibrosis: Causes and Risk Factors. Accessed November 2026.
- 4. In vitro and in vivo pharmacokinetic characterization, chiral conversion and PBPK scaling towards human PK simulation of S-MRI-1867, a drug candidate for Hermansky-Pudlak syndrome pulmonary fibrosis. DOI: 10.1016/j.biopha.2023.115178 PMID: 37890204
- 5. National Heart, Lung, and Blood Institute. Pulmonary Fibrosis: Diagnosis. Accessed November 2026.
- 6. MedlinePlus, National Library of Medicine. Cystic Fibrosis. Accessed November 2026.
- 7. National Heart, Lung, and Blood Institute. Pulmonary Fibrosis Treatment. Accessed November 2026.
- 8. National Heart, Lung, and Blood Institute. Pulmonary Fibrosis: Living With. Accessed November 2026.
- 9. Therapeutic Potential of Cannabinoids in Attenuating Amiodarone-Induced Pulmonary Fibrosis: An in vivo Experimental Study in Wistar Rats. DOI: 10.2147/DDDT.S570825 PMID: 41804454
- 10. Activation of cannabinoid receptor type 2 by JWH133 alleviates bleomycin-induced pulmonary fibrosis in mice. DOI: 10.18632/oncotarget.21975 PMID: 29262578
- 11. A selective CB2R agonist (JWH133) protects against pulmonary fibrosis through inhibiting FAK/ERK/S100A4 signaling pathways. DOI: 10.1186/s12890-023-02747-3 PMID: 37957604
- 12. Discovery of a pyrano[2,3-b]pyridine derivative YX-2102 as a cannabinoid receptor 2 agonist for alleviating lung fibrosis. DOI: 10.1186/s12967-022-03773-1 PMID: 36474298
- 13. Cannabinoid Analogue WIN 55212-2 Protects Paraquat-Induced Lung Injury and Enhances Macrophage M2 Polarization. DOI: 10.1007/s10753-022-01688-z PMID: 35674874
- 14. Targeting cannabinoid receptor 1 for antagonism in pro-fibrotic alveolar macrophages mitigates pulmonary fibrosis. DOI: 10.1172/jci.insight.187967 PMID: 40608428
- 15. An Integrative Multiomics Framework for Identification of Therapeutic Targets in Pulmonary Fibrosis. DOI: 10.1002/advs.202207454 PMID: 37038090
- 16. ACPA Alleviates Bleomycin-Induced Pulmonary Fibrosis by Inhibiting TGF-β-Smad2/3 Signaling-Mediated Lung Fibroblast Activation. DOI: 10.3389/fphar.2022.835979 PMID: 35355726
- 17. Ajulemic acid exerts potent anti-fibrotic effect during the fibrogenic phase of bleomycin lung. DOI: 10.1186/s12931-016-0373-0 PMID: 27153807