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in the treatment of Inflammatory Bowel Disease (IBD)



  • There are many different opinions in the community about the use of cannabis (marijuana) in the treatment of a wide variety of health conditions. 

  • Cannabis use has increased over the past several years including at younger ages. Up to 1 in 5 persons using cannabis may be considered to have a cannabis use disorder, meaning that they are using it excessively.

  • The two main chemicals in cannabis are tetrahydracannabinol (THC) and cannabidiol (CBD). THC can be mind-altering. CBD may have more gastrointestinal effects and limited mind effects.

  • Cannabis that is currently available is much more potent than cannabis that was available prior to the 2000s.

  • Prescription cannabis prescribed by a physician has been available in Canada and in several states in America for several years. On October 17, 2018 the Cannabis Act came into effect across Canada. It meant that persons who are aged 18 years or older can possess up to 30 grams of legal cannabis in its dried or “equivalent non-dried form” in public.

  • Cannabis products can be purchased with different ratios of THC to CBD.

  • Some people with IBD use cannabis for symptom relief.

  • One survey from University of Calgary indicated that cannabis had been used by nearly 1 in 5 (18%) respondents to relieve symptoms associated with IBD. Cannabis was reported to primarily improve abdominal pain cramps and to a lesser extent diarrhea.

  • A survey from University of Toronto found that 1 in 7 people (14%) with IBD used cannabis for symptom relief.

  • In an outpatient survey of persons with IBD at the University of Manitoba 54% reported lifetime cannabis use.  Of cannabis users more persons with Crohn’s disease (53%) than ulcerative colitis (28%) used cannabis to manage their IBD symptoms.

  • Persons self-medicating with cannabis were more likely to use cannabis for coping reasons and depressive symptoms when compared to individuals using cannabis recreationally.

  • Smokers were 4x more likely and persons with moderate to severe depressive symptoms were more likely to use cannabis for IBD symptoms

  • It was concluded from this Manitoba study that screening for mental health comorbidities and vulnerability to substance misuse should be undertaken if cannabis is to be used to treat IBD symptoms. 

  • The use of cannabis has some risks related to how it is used (smoked, orally, vaporizer) and the influence of cannabis on driving and other daily activities.



  • As in other health conditions there has been limited research on the use of cannabis in IBD.

  • One small but well-controlled study in Crohn’s disease compared cannabis cigarettes with placebo cigarettes (not containing an active substance).  These patients had a limited response to previous medication treatments.  Patients receiving the active cannabis had a considerably larger reduction in symptoms than those receiving placebo. 

  • There was no evidence from the study that cannabis reduced inflammation – it appeared to mainly influence symptoms. 

  • When patients stopped the cannabis, there was a relapse of symptoms within two weeks, suggesting that cannabis had not had major effects on inflammation.

  • The authors suggested that more research is necessary to understand the effects of cannabis in IBD.

  • The authors recommended that, since cannabis does not have an effect on inflammation, it should be reserved for compassionate use only in patients who have exhausted all other medical and surgical options.  There is a risk that if patients rely only on cannabis the inflammation associated with IBD may not be treated.

  • The same team, in a more recent study. evaluated the effects of a component of cannabis, CBD, in a low dose in a small trial with patients with active symptoms of Crohn’s disease.  They found that the treatment was no more effective than placebo (a pill with no active ingredients).  They concluded that further research is needed to evaluate whether component substances in cannabis influence symptoms and at what doses.


Overall Research of the Health Effects of Cannabis


  • The National Academies of Sciences in the US recently completed a comprehensive review of the health impacts (positive and negative) of cannabis.  They considered the strength of the evidence of various health effects. 

  • Positive effects:  They found strong evidence that cannabis has a significant influence on reducing chronic pain in adults. Most of the studies evaluated the use of cannabis in smoked or vaporized forms and there were few studies evaluating it in other forms such as in edibles or pill or liquid form.  Little is known about the doses that are effective and the side effects of cannabis use for chronic pain.

  • Negative effects: Cannabis use is associated with increased motor vehicle accidents.  Cannabis use impairs the performance in learning, memory, and attention at least while the substance is active in the body. Use during adolescence is related to impairments in academic achievement and education, employment and income, and social relationships.





Hansen TM, Sabourin BC, Oketola B, Bernstein CN, Singh H, Targownik LE. Cannabis use in persons with inflammatory bowel disease and vulnerability to substance misuse. Inflammatory Bowel Diseases 2020; in press.


Hasenoehrl C, Storr M, Schicho R. Cannabinoids for treating inflammatory bowel diseases: where are we and where do we go? Expert Review of Gastroenterology & Hepatology 2017, 11:4, 329-337, DOI: 10.1080/17474124.2017.1292851


Naftali T, Bar-Lev Schleider L, Dotan I, et al. Cannabis induces a clinical response in patients with Crohn's disease: a prospective placebo-controlled study. Clinical Gastroenterology and Hepatology 2013; 11(10):1276-1280.


Naftali T, Mechulam R, Marii A, Gabay G, Stein A, Bronshtain M, Laish I, Benjaminov F, Konikoff FM.  Low-Dose Cannabidiol Is Safe but Not Effective in the Treatment for Crohn's Disease, a Randomized Controlled Trial.  Digestive Diseases and Sciences 2017 Jun;62(6):1615-1620. doi: 10.1007/s10620-017-4540-z.


National Academies of Sciences, Engineering, and Medicine. The health effects of cannabis and cannabinoids: The current state of evidence and recommendations for research.  2017. Washington, DC: The National Academies Press. doi: 10.17226/24625.

Last reviewed: March 2020

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Disclaimer: This information is provided for educational purposes only. Always consult a qualified health care professional for your specific care.

Source: This summary provides scientifically accurate information.  It was prepared in a research review by researchers with the IBD Clinical and Research Centre, University of Manitoba with assistance from colleagues in Canada and internationally. 

Acknowledgement:  Preparation of this material was supported by funding from the Canadian Institutes of Health Research. 

2017 Charles N. Bernstein, John R. Walker on behalf of Manitoba IBD Clinical and Research Centre. This work is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License. You are free to copy and distribute this material in its entirety, as long as it is not altered in any way (no derivative works).

Last reviewed March, 2020

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