Cannabinoids for Chemotherapy-Related Nausea and Vomiting: Evidence Review

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Nausea and vomiting from chemotherapy needs the cancer care team. This page summarizes research and does not suggest using any cannabis product during cancer treatment. Tell your oncology team about every cannabis or CBD product you use, because they can add sleepiness and interact with other medicines. Evidence labels used: approved medicine, mixed, insufficient evidence and no good evidence of benefit. Laws and approvals change; this is not legal advice.

Three different things

What regulators say

• United States. Dronabinol is approved for adults with chemotherapy nausea and vomiting who have not responded adequately to conventional anti-sickness treatment. [3][4] The FDA lists nabilone as an approved drug too. [1]
• England. NICE says to consider nabilone as an add-on for adults whose chemotherapy nausea persists despite optimized usual antiemetics, and to watch for interactions with sedating medicines. [5] The NHS says medical cannabis is most likely to be prescribed there for adults with chemotherapy nausea or vomiting among a few conditions. [6]
• Oncology guidelines. The National Cancer Institute's summary reports that ASCO guidelines (2017) recommended the approved cannabinoids for nausea resistant to standard treatment, and that the 2020 update found evidence insufficient to recommend medical marijuana for preventing or treating it. [2]

What the research shows

Versus placebo: favorable, but the trials are old. A Cochrane review of 23 trials, conducted between 1975 and 1991, found more people had no vomiting or no nausea and vomiting with cannabinoids than with placebo. They also withdrew more often because of side effects and were far more likely to feel "high". [7] No trial compared them with newer drugs such as ondansetron. [7]

Versus older anti-sickness drugs: no clear difference. In the same review there was no difference from prochlorperazine in no nausea or no vomiting, and more people stopped cannabinoids because of side effects. [7]

Newer analysis. A 2025 meta-analysis of 26 randomized trials (23 published before the 2000s) found cannabinoids beat placebo (risk ratio 2.65) but did not differ from active treatments, most of them dated single-drug regimens. [8] It concluded there is scant evidence of benefit in the era of triple and quadruple anti-sickness regimens. [8]

One newer trial. In an Australian and New Zealand trial of 147 people, a THC and CBD capsule added to guideline antiemetics had a higher response than placebo (24% versus 8%), with more sedation, transient anxiety and dizziness. [2] The 2025 meta-analysis noted this trial and called for studies alongside regimens that include olanzapine. [8]

Combined view. A 2026 JAMA review reports a small but significant reduction in nausea and vomiting with prescribed cannabinoids (dronabinol, nabilone) compared with placebo or active comparators, and says guidelines do not recommend inhaled or high-potency cannabis for medical use. [9] Labels: approved medicine and mixed for the approved drugs; insufficient evidence for smoked cannabis and for store products.

Risks and warnings

The dronabinol label lists abdominal pain, dizziness, euphoria, nausea, paranoid reaction, sleepiness, abnormal thinking and vomiting among the most common adverse reactions. [3] It warns of psychiatric and cognitive effects, advises avoiding use in people with a psychiatric history, asks prescribers to assess misuse risk, and notes older adults may be more sensitive. [3] It also warns that nausea, vomiting or abdominal pain can paradoxically worsen. [3]

Long-term, heavy cannabis use can itself cause repeated vomiting; see cannabinoid hyperemesis syndrome. NIDA describes it as nausea, vomiting and abdominal pain after long-term heavy use. [10]

Where to read next

Approved cannabinoid medicines compares dronabinol, nabilone, nabiximols and CBD. Cannabis medicines vs consumer products explains why trial results do not transfer. For non-drug options, see acupuncture for postoperative nausea and other uses. Drug interactions are in cannabis and CBD medicine interactions.