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CBD for IBS, Crohn's and colitis

Small controlled trials found CBD no better than placebo for Crohn's disease and IBS pain. For ulcerative colitis there is not enough evidence.

Facts checked 13 November 20265 min readHow we research
Trials show no benefit

Small trials found no benefit for Crohn's disease (10 mg twice a day) or IBS pain (50 mg chewing gum). For ulcerative colitis the evidence is insufficient, with one trial showing similar remission rates to placebo.

How we grade evidence

Small controlled trials have found CBD no better than placebo for Crohn’s disease and for pain in irritable bowel syndrome (IBS). For ulcerative colitis there is not enough evidence either way. The trials were small and mostly used low doses, so they do not rule out an effect at higher doses, but nothing so far supports one.

IBS and inflammatory bowel disease (IBD) are different conditions. IBS causes pain and changed bowel habits without visible damage to the gut. IBD, which includes Crohn’s disease and ulcerative colitis, involves inflammation that damages the bowel.

What the research shows

Condition Our grade Trial Result
Crohn’s disease Trials show no benefit 20 people, CBD 10 mg twice a day, 8 weeks No difference from placebo
IBS Trials show no benefit 32 women, 50 mg CBD chewing gum, crossover No significant difference in pain
Ulcerative colitis Not enough evidence 60 people, CBD-rich extract, 10 weeks Remission 28% vs 26% on placebo

Crohn’s disease

Naftali and colleagues (2017) randomised 20 people with moderately active Crohn’s disease to 10 mg of oral CBD or placebo twice a day for 8 weeks. Nineteen completed the study. Disease activity scores at 8 weeks were about the same: 220 in the CBD group and 216 in the placebo group. No side effects were seen. The authors concluded CBD was “safe but not effective”, and suggested the low dose, the small sample or the lack of other cannabinoids might explain the result.12

Ulcerative colitis

Irving and colleagues (2018) tested a CBD-rich botanical extract, meaning a plant extract and not pure CBD, in 60 people for 10 weeks. Remission occurred in 28% of the extract group and 26% of the placebo group.3

Crohn’s and colitis together

A Cochrane-based summary found 5 randomised trials with 185 participants across Crohn’s disease and ulcerative colitis, covering cannabis and cannabinoids in general. It concluded the effects were uncertain.4

IBS

A crossover trial gave 32 women with IBS chewing gum containing 50 mg of CBD or a placebo gum at different times. There was no significant difference in pain.5

What doses were tested

The doses were low: 20 mg a day in the Crohn’s trial and 50 mg per piece of gum, used as needed, in the IBS trial.15 Both are within the 150 mg a day limit for pharmacist-only (Schedule 3) CBD in Australia.6

A review by Australian researchers found the benefits of oral CBD in other conditions “became more clearly evident” at 300 mg a day or more.7 No trial at that level for Crohn’s disease or IBS was found in our research. So the fair summary is that low doses have been tested and did not work, and higher doses are untested. See does low-dose CBD work?

What Australian medical bodies say

No Australian medical body recommends CBD for IBS, Crohn’s disease or ulcerative colitis.

  • The TGA says medicinal cannabis should be considered only when registered medicines have been tried and have failed.8
  • RACGP (the GPs’ college) describes the evidence as “limited and inconclusive” and does not recommend or encourage medicinal cannabis.9
  • No cannabis medicine is registered in Australia for any bowel condition.10

See what Australian medical bodies say about CBD.

Risks to know about

  • Diarrhoea. A pooled analysis of randomised trials found CBD was linked to diarrhoea (odds about 2.6 times those on placebo). After childhood epilepsy studies were excluded, diarrhoea was the only side effect still linked to CBD.11 In a review of trials from 2020 to 2022, gut-related events made up 59.5% of reported side effects.12
  • Reduced appetite. This was also more common with CBD than placebo in trials.13 It matters if you are already losing weight.
  • Interactions. CBD can raise blood levels of some medicines that suppress the immune system. A case report described a roughly 3-fold rise in tacrolimus after CBD was added.14 If you take any immune-suppressing medicine for IBD, your specialist needs to know. See CBD drug interactions.
  • Liver. CBD can raise liver enzymes, more often at higher doses.13 See CBD and the liver.

If you are considering it

  • Talk to your gastroenterologist or GP first, and keep taking your prescribed IBD medicines unless they advise otherwise.
  • Ask what dose and product the evidence relates to, and whether the product contains THC.
  • Have your full medicine list checked for interactions.
  • If any new treatment is started, track your symptoms before and after so any change can be judged fairly.

See talking to your GP about CBD.

Footnotes

  1. Naftali T et al. Low-dose cannabidiol is safe but not effective in the treatment for Crohn’s disease, a randomized controlled trial. Digestive Diseases and Sciences, 2017. https://pubmed.ncbi.nlm.nih.gov/28349233/ ↩ ↩2

  2. ClinicalTrials.gov. Cannabidiol for inflammatory bowel disease, NCT01037322. https://clinicaltrials.gov/study/NCT01037322 ↩

  3. Review of cannabis in inflammatory bowel disease, reporting Irving PM et al., 2018 (secondary source). https://www.rmmj.org.il/userimages/1005/1/PublishFiles/1027Article.pdf ↩

  4. Summary of Cochrane reviews of cannabis for Crohn’s disease and ulcerative colitis. https://pubmed.ncbi.nlm.nih.gov/31613959/ ↩

  5. Randomised crossover trial of cannabidiol chewing gum in irritable bowel syndrome. https://pubmed.ncbi.nlm.nih.gov/33998882/ ↩ ↩2

  6. Therapeutic Goods Administration. Final decision on the scheduling of low-dose cannabidiol, 2020. https://tga.gov.au/node/284859 ↩

  7. Arnold JC, McCartney D, Suraev A, McGregor IS. The safety and efficacy of low oral doses of cannabidiol. Clinical and Translational Science, 2023. https://pubmed.ncbi.nlm.nih.gov/36259271/ ↩

  8. Therapeutic Goods Administration. Guidance for the use of medicinal cannabis in Australia: overview. https://www.tga.gov.au/resources/resource/guidance/guidance-use-medicinal-cannabis-australia-overview ↩

  9. Royal Australian College of General Practitioners. Medical cannabis position statement (2019 update). https://www.racgp.org.au/advocacy/position-statements/view-all-position-statements/clinical-and-practice-management/medical-cannabis ↩

  10. NPS MedicineWise. Medicinal cannabis: what you need to know. https://www.nps.org.au/professionals/medicinal-cannabis-what-you-need-to-know ↩

  11. Chesney E et al. Adverse effects of cannabidiol: a systematic review and meta-analysis of randomized clinical trials, 2020. https://pubmed.ncbi.nlm.nih.gov/32268347/ ↩

  12. Review of adverse events in randomised trials of oral cannabidiol, 2020 to 2022. https://pmc.ncbi.nlm.nih.gov/articles/PMC9782576/ ↩

  13. Epidiolex (cannabidiol) US prescribing information, DailyMed, revised 2026. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8bf27097-4870-43fb-94f0-f3d0871d1eec ↩ ↩2

  14. Systematic review of cannabidiol drug interactions. https://pmc.ncbi.nlm.nih.gov/articles/PMC11167383/ ↩

Common questions

Does CBD help IBS?

The one controlled trial found it did not. Thirty-two women with IBS used chewing gum containing 50 mg of CBD or a placebo gum, and there was no significant difference in pain. Other forms and doses of CBD have not been tested for IBS in the research we reviewed.

Does CBD help Crohn's disease?

A small trial found no benefit. Twenty people with active Crohn's disease took 10 mg of CBD or placebo twice a day for 8 weeks, and disease activity scores were about the same in both groups at the end. The authors suggested the low dose and small size may have played a part.

Does CBD help ulcerative colitis?

There is not enough evidence to say. In one 10-week trial of a CBD-rich plant extract in 60 people, 28 percent of the extract group and 26 percent of the placebo group went into remission. A summary of five small trials across Crohn's and colitis concluded the effects were uncertain.

Can CBD upset your stomach?

Yes. Diarrhoea is one of the most consistently reported side effects of CBD in trials, along with reduced appetite. That is worth knowing if your main symptoms are in the gut.

This page is general information, not medical or legal advice. Laws and evidence change; we show the date we last checked the facts at the top of every page. Talk to your doctor or pharmacist before starting, stopping or changing any medicine.

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