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Can Marijuana Help Treat Asthma?
Problems with Conventional Asthma Treatment

While smoking marijuana may seem bad for your lungs, studies show it can actually be helpful for treating asthma.

For those unfamiliar with the effects of marijuana on the body, using it to treat asthma may seem counterintuitive. Marijuana is usually associated with smoking, which is considered to have a negative impact on the lungs.

But evidence suggests that compounds in marijuana can actually help asthma sufferers.

The anti-inflammatory, anti-spasmodic, and anti-anxiety properties of marijuana make it a good candidate for treating asthma. Marijuana may also address some of the problems with conventional treatments like puffers.

In this article, we will take a look at the science of marijuana and asthma.

What is Asthma?

Lungs that may have asthma
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Asthma is a chronic condition causing inflammation of the airways in the lungs. Inflammation of these airways (bronchioles) results in breathing difficulties. Symptoms include shortness of breath, chest tightness, coughing and wheezing.

The breathing troubles experienced during an asthma attack are caused by two main factors. First, the muscles that surround the bronchioles tighten. And secondly, the bronchioles produce more mucus.

The condition is often triggered by environmental exposures to irritants that enter the lungs. This can include allergens such as pollen and mold.

Other factors such as stress and anxiety can contribute to an increase in symptoms. This is due to the physiological changes that take place during a stressful event. In particular, the increased release of histamines and leukotrienes narrow the airways in the lungs.

Asthma usually does not go away or remit completely, but remission is possible in milder forms of the disease.

Problems with Conventional Treatment

Asthma puffers and medications
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Asthma sufferers are often prescribed inhalers or puffers to treat their condition. These inhalers typically contain steroids.

Steroids act to reduce inflammation in the lungs as well as mucous production. Both of these actions reduce the likelihood of an asthma attack when exposed to triggers.

While these inhalers help many patients living with asthma, they aren’t a perfect solution.

To start, they are slow to take effect, sometimes requiring several hours. Several hours is too long to wait during an asthma attack. This is why the inhalers must be used regularly as a preventative measure.

Inhaled steroids also carry side effects, such as voice hoarseness and thrush (a yeast infection of the mouth).

Other Medications

Systemic Steroids — Some patients also take steroids by mouth, known as systemic steroids. These can have even more severe side effects. Because they pass through the digestive system, they affect the whole body, not just the lungs.

Side effects include slowed growth, bone loss, upset stomach, weight gain, and mood changes.

Leukotriene Modifiers — Asthma patients may also take a medication to target the compounds causing inflammation. These compounds, called leukotrienes, increase mucus production in lungs and tighten muscles surrounding the airways. “Leukotriene modifying medications” reduce symptoms by targeting these compounds.

Leukotriene modifying medications also carry side effects. These include insomnia, headache, irritability, nausea and vomiting.

Immunomodulators — Another type of asthma medication is known as immunomodulators. This drug also targets inflammatory chemicals involved in asthma, known as cytokines.

Immunomodulators block certain cytokines from binding to white blood cells. This prevents the inflammatory response that produces asthma attacks.

Immunomodulators are only used in cases of asthma where steroids failed to help. Their side effects can include dizziness, headache, difficulty breathing and hives.

Can Marijuana Help Treat Asthma?

Marijuana used to treat asthma.
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Much of the research on marijuana and asthma took place in the 1970s. Regardless, there is plenty of evidence that marijuana can help treat asthma.

Marijuana acts as a bronchodilator, anti-spasmodic and anti-anxiety medication, all of which contribute to improving asthma.

Researchers first discovered marijuana’s ability to act as a bronchodilator in 1973. This study, which was conducted on healthy volunteers, sparked interest in marijuana’s potential to treat asthma.

Further research was conducted in 1974 to investigate marijuana’s effects on asthma sufferers. The study found that smoked marijuana also acts as a bronchodilator in people with asthma.

A 1975 study published in the American Review of Respiratory Disease used an induced model of asthma. They induced airway contractions (bronchospasms) in healthy volunteers to replicate asthma.

The scientists found that marijuana (containing 2% THC) relieved symptoms of bronchospasms. By contrast, many strains available today contain 10-20% THC.

After smoking 0.5 grams of the 2% THC marijuana, the participants recovered immediately from the bronchospasms and overinflation of the lungs.

Other studies from 1976 and 1978 provide further support for these findings. The studies found that very small doses of THC, when applied through an inhaled aerosol, worked as a bronchodilator in patients with asthma.

These early studies suggest that smoked marijuana is effective against asthma. It helps open up the airways of the lungs through bronchodilation, and also reduces muscle spasms in the airways, allowing air to be exhaled more readily.

Compounds in marijuana, such as CBD, are also known to reduce anxiety at appropriate doses. This makes marijuana effective at not only relieving the inflammation and muscular contractions associated with asthma, but also at relieving the anxiety and stress that contributes to asthma attacks.

Effects of Marijuana on Asthma

Marijuana treatments for asthma
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A 1976 study showed that THC acts as an effective and immediate bronchodilator in patients with asthma. Researchers administered THC as an aerosol spray at doses of only 200 μm (1/5th of a milligram).

Even at this tiny dose, THC was found to have a similar effect to salbutamol, a common anti-asthma medication.

Stress and Anxiety

Marijuana is known to be effective at regulating stress and anxiety. Since stress is a contributing factor to asthma, this benefit of marijuana makes it unique among other asthma treatments.

Using marijuana to relieve stress may reduce asthma in sufferers, especially during periods of heightened stress and anxiety.


The cannabinoid CBD (cannabidiol) has strong anti-inflammatory effects. Specifically, it has been found to reduce inflammation in lung tissues.

CBD has also been found to reduce the production of inflammatory compounds in the lungs, known as cytokines.


In a 2015 study conducted in Brazil, CBD was found to reduce the mucosal production that is common in asthma.

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CBD decreased the production of cytokines, which are responsible for producing mucus in the lungs.


In a 2014 study, scientists showed that THC and other cannabinoids can reduce contractions in the lungs.

Lung contractions (or spasms) can contribute to asthma attacks. THC acts on CB1 receptors to reduce these contractions. The effect is dose-dependent, meaning it increases with larger doses. In the study, the maximum reduction of symptoms observed was 39%.

How to Use Marijuana For Asthma

Prescription marijuana to treat asthma
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Avoid Smoking

Because smoke is hot and irritating, it is not an ideal method of marijuana consumption for the treatment of asthma. Some studies suggest that regular intake of marijuana smoke may promote inflammation in the lungs.

Marijuana smoke contains similar chemical compounds to smoke from tobacco products (e.g. tar). But despite this, smoking marijuana does not increase the risk of cancer.

On the other hand, heavy smoking of marijuana may result in decreased lung function. For example, chronic marijuana smokers may show reduced lung capacity.

Since marijuana smoke is irritating to the lungs, it makes sense that asthmatics should avoid this method.


Marijuana edibles may be useful for treating symptoms of asthma, but only under certain circumstances. Since edibles must be processed by the digestive system, it takes longer for them to take effect.

This makes edibles an impractical solution during an asthma attack.

But when used on a regular basis, oral consumption of cannabis may be helpful as a supplement or replacement for systemic steroids.


Rather than inhaling smoke, asthma sufferers can vaporize their marijuana instead. Vaporizing avoids most of the toxins in marijuana smoke that irritate the lungs. At the same time, it effectively delivers the beneficial compounds in marijuana.

Much like smoking marijuana, vaporizing is a rapid method of administering cannabinoids. In other words, the effects can be felt instantly.

Vaporizing is similar to the inhalation of THC aerosols used in studies, which were found to provide immediate relief from symptoms of asthma.


Marijuana may offer a number of benefits to asthma sufferers.

Marijuana can act as an effective and fast-acting bronchodilator. It also has anti-spasmodic, anti-mucosal, and anti-anxiety properties. All of these can help ease breathing and improve symptoms of asthma.

When it comes to using marijuana to relieve symptoms of asthma, smoking it is not ideal. Smoke of any kind may irritate the lungs, so it is best if patients with asthma vaporize instead.

Vaporizing does not produce the irritating compounds found in smoke. At the same time, it delivers the beneficial compounds in marijuana known as cannabinoids.

Although research on marijuana and asthma is sparse, there is evidence suggesting that it could be useful as an alternative treatment.

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