Asthma and Cannabis

I have been doing cannabis recommendations for over a decade. Most of the time patients come in for a recommendation for pain or other condition. As I review their past medical history, they tell me that they had asthma in the past and rarely have an attack, but they keep a rescue inhaler. I ask them when they had their frequent attacks and when they stopped having frequent attacks. I ask them when they started using cannabis. Invariably, the tell me that their symptoms stopped when they started using cannabis.

For most people, the idea of inhaling marijuana to treat the symptoms of asthma is simply unheard of. It’s common knowledge that smoking cigarettes can worsen asthma symptoms, and most people can’t imagine how inhaling anything (besides the medicine contained in a doctor-prescribed inhaler, of course) could have health benefits.

Credits for the following:

Cannabis, however, can have positive effects on the symptoms of asthma

  • even when inhaled. These new findings are an exciting development for those suffering from the lung disease. It’s possible that with further study, we’ll soon be seeing marijuana emerge as a mainstream treatment for this chronic condition.

What is Asthma?

Asthma is a dangerous respiratory condition that results in difficulty breathing. Asthma attacks – characterized by coughing, wheezing and shortness of breath – are often the result of exercise or allergic reactions to environmental pollutants, like pollen or dander. With symptoms that range from mild to severe, asthma is a common disorder that affects more than 25 million Americans. More than 3,000 people in the United States die each year from asthma-related complications.

How Cannabis Treats Asthma Symptoms

It’s widely known that cannabis is a powerful anti-inflammatory. One of the main ways cannabis treats asthma symptoms is by discouraging inflammation and opening the passages of the respiratory system. This, in turn, decreases coughing and shortness of breath. While many people may imagine the effects of smoking marijuana and smoking cigarettes to be similar, the effects of marijuana on the bronchial passages are actually the opposite of tobacco cigarettes – which constrict the passages of the airway, causing asthma symptoms to worsen.

A 2012 study published in The Journal of the American Medical Association found that people who suffered from asthma and smoked marijuana on a moderate basis actually increased their lung function, without suffering the lung damage associated with tobacco cigarettes.

These results have surprised almost everyone, from consumers to doctors who specialize in the diagnosis and treatment of asthma. It’s clear the effectiveness of medical marijuana on asthma symptoms has the potential to revolutionize how the condition is treated in the future.

Cannabis Vaporizers vs. Corticosteroids

One thing many medical professionals are considering is whether cannabis can replace or decrease the use of corticosteroids for the treatment of asthma. Inhalers containing corticosteroids are currently the most-diagnosed treatment for asthma, but unfortunately, the medications contained within prescribed inhalers have been associated with dangerous side effects/Pages/Sideeffects.aspx), including depression, anxiety and high blood pressure. Because of this, many asthma sufferers have been looking for steroid-free treatment solutions – and marijuana is currently one of the leading options.

One of the best ways to deliver cannabis to a person suffering from asthma is through vaporization. Modern inhalers work by vaporizing the medicine within, so it stands to reason marijuana vaporizers could become just as popular in the asthmatic community. In addition to being safer and cleaner than smoking, vaporizers are also highly portable, efficient and effective. Because of these characteristics, cannabis vaporizers could easily replace vaporized corticosteroids with a safer and more effective medicine.

The Bottom Line

While only time will tell whether marijuana gains popularity as a treatment for asthma, it’s clear the compounds contained within marijuana (including THC and CBD) possess powerful anti-inflammatory properties that can help decrease and alleviate the symptoms of asthma. Additionally, the easy availability and proven effectiveness of delivery methods like marijuana vaporization can help asthma sufferers have access to a safe, efficient treatment to manage their symptoms.

Vaporization as a Safer Alternative to Smoking

While growing evidence demonstrates the anti-inflammatory properties of CBD and certain benefits of THC(CBD and THC are phytocannabinoids, or cannabinoids found in cannabis), the burning of plant material (e.g. smoking cannabis) releases cancer-causing compounds. While (1) there is no compelling evidence to support the idea that smoking cannabis causes cancer (partially due to the growing evidence that suggests that certain cannabinoids may have anti-cancer properties) and (2) at low to moderate frequency of use, cannabis smoking has not been showing to cause lung dysfunction, vaporization (heating to release vapors, rather than burning) is a safer inhalation method.

The inhalation of marijuana smoke is unnecessary for the experience of its potential benefits– even when an inhalation delivery method is best for an individual patient and their unique symptoms, vaporization is a safer and similarly effective option. If you currently smoke cannabis, switching to vaporization is a healthier option.

Cannabinoids Proven to Enhance Lung Function

While marijuana smoke has some of the same toxins as tobacco smoke, the cannabinoids found in cannabis work in a way to counter act the harmful effects of the smoke. So are your lungs actually ever really damaged? This is yet to be proven.

Studies have demonstrated that THC may act as a temporary (1-2 hours) bronchodilator, especially when ingested. The New England Journal of Medicine, published a 1973 study that stated, “Marihuana smoke, unlike cigarette smoke, causes broncho-dilation rather than broncho-constriction [narrowing of the air passages] and, unlike opiates, does not cause central respiratory depression [i.e. a decrease in breathing].”

Another long-term study (20 years) done from 1985 to 2006, examined 5,000 subjects from three American cities. The researchers questioned the participants about their cannabis and cigarette use, and tested lung capacity as well as rate of air flow out of their lungs. To their surprise, the researchers found that at low to moderate levels of cannabis smoking, lung volume and air flow rates both increased with each “joint year” (365 joints), up until seven joint-years (or 2,555 joints).

“Marijuana smoke, unlike cigarette smoke, causes broncho-dilation [opening] rather than broncho-constriction [narrowing of the air passages] and, unlike opiates, does not cause central respiratory depression.” – New England Journal of Medicine

While some may argue that lung capacity is increased because of long inhales and the holding of breath that goes with cannabis smoking, that doesn’t explain why the lungs of cannabis-only smokers didn’t worsen like the lungs of cigarette smokers. There is more happening behind the scenes.

Oral administration (and perhaps vaporization) of cannabinoids may open up your airways, acting as a bronchodilator. Some asthmatics have found relief through the use of Marinol, a synthetic (man-made) pill-form of THC. Although the drug has greater psychoactive properties than actual cannabis and may be less effective than whole-plant cannabis for certain conditions, it is still more effective than inhalers or nebulizers for most patients. Asthma patients may benefit from the ingestion of cannabis because of its anti-inflammatory effects, through the use of edibles or tincture. For patients that have serious cases of asthma, ingesting hemp oil in its raw form could provide long-term preventative relief as an alternative to smoking.

Cannabis May Help Cleanse Sinuses & Lungs

Doctors often suggest that patients use a neti pot to clear clogged sinuses (a frequent problem among asthma patients) in the morning. Some people dislike this method because it just feels weird, and is not exactly what someone looks forward to doing each and every morning.


Needless to say, much more scientific research must be done to assess the effect of various cannabis delivery methods on asthma patients. With over 35 million people affected each year by asthma, finding safe and effective treatment options to commonly used medications that may produce adverse sideeffects is essential.

Research Sudies

See comment in PubMed Commons below

Am Rev Respir Dis. 1975 Sep;112(3):377-86.

Effects of smoked marijuana in experimentally induced asthma.

Tashkin DP, Shapiro BJ, Lee YE, Harper CE.


After experimental induction of acute bronchospasm in 8 subjects with clinically stable bronchial asthma, effects of 500 mg of smoked marijuana (2.0 per cent delta9-tetrahydrocannabinol) on specific airway conductance and thoracic gas volume were compared with those of 500 mg of smoked placebo marijuana (0.0 per cent delta9-tetrahydrocannabinol), 0.25 ml of aerosolized saline, and 0.25 ml of aerosolized isoproterenol (1,250 mug). Bronchospasm was induced on 4 separate occasions, by inhalation of methacholine and, on four other occasions, by exercise on a bicycle ergometer or treadmill. Methacholine and exercise caused average decreases in specific airway conductance of 40 to 55 per cent and 30 to 39 per cent, respectively, and average increases in thoracic gas volume of 35 to 43 per cent and 25 to 35 per cent, respectively. After methacholine-induced bronchospasm, placebo marijuana and saline inhalation produced minimal changes in specific airway conductance and thoracic gas volume, whereas 2.0 per cent marijuana and isoproterenol each caused a prompt correction of the bronchospasm and associated hyperinflation. After exercise-induced bronchospasm, placebo marijuana and saline were followed by gradual recovery during 30 to 60 min, whereas 2.0 per cent marijuana and isoproterenol caused an immediate reversal of exercise-induced asthma and hyperinflation.

Br J Clin Pharmacol. 1978 Jun; 5(6): 523–525.

PMCID: PMC1429361

Bronchodilator effect of delta1-tetrahydrocannabinol.

J P Hartley, S G Nogrady, and A Seaton

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This article has been cited by other articles in PMC.


1 delta1-trans-tetrahydrocannabinol, (delta1-THC) produces bronchodilatation in asthmatic patients. 2 Administered in 62 microliter metered volumes containing 50–200 microgram by inhalation from an aerosol device to patients judged to be in a steady state, it increased peak expiratory flow rate (PEFR) and forced expiratory volume in 1 second (FEV1). 3 The rate of onset, magnitude, and duration of the bronchodilator effect was dose related.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Davies BH, Radcliffe S, Seaton A, Graham JD. A trial of oral delta-1-(trans)-tetrahydrocannabinol in reversible airways obstruction. Thorax. 1975 Feb;30(1):80–85. [PMC free article] [PubMed]
  • Henderson RL, Tennant FS, Guerry R. Respiratory manifestations of hashish smoking. Arch Otolaryngol. 1972 Mar;95(3):248–251. [PubMed]
  • Tashkin DP, Shapiro BJ, Frank IM. Acute pulmonary physiologic effects of smoked marijuana and oral 9 -tetrahydrocannabinol in healthy young men. N Engl J Med. 1973 Aug 16;289(7):336–341. [PubMed]
  • Tashkin DP, Shapiro BJ, Frank IM. Acute effects of smoked marijuana and oral delta9-tetrahydrocannabinol on specific airway conductance in asthmatic subjects. Am Rev Respir Dis. 1974 Apr;109(4):420–428. [PubMed]
  • Tashkin DP, Shapiro BJ, Lee YE, Harper CE. Effects of smoked marijuana in experimentally induced asthma. Am Rev Respir Dis. 1975 Sep;112(3):377–386. [PubMed]
  • Tashkin DP, Reiss S, Shapiro BJ, Calvarese B, Olsen JL, Lodge JW. Bronchial effects of aerosolized delta 9-tetrahydrocannabinol in healthy and asthmatic subjects. Am Rev Respir Dis. 1977 Jan;115(1):57–65. [PubMed]
  • Vachon L, FitzGerald MX, Solliday NH, Gould IA, Gaensler EA. Single-dose effects of marihuana smoke. Bronchial dynamics and respiratory-center sensitivity in normal subjects. N Engl J Med. 1973 May 10;288(19):985–989. [PubMed]
  • Williams SJ, Hartley JP, Graham JD. Bronchodilator effect of delta1-tetrahydrocannabinol administered by aerosol of asthmatic patients. Thorax. 1976 Dec;31(6):720–723. [PMC free article] [PubMed]