A meta-analysis of 26 RCTs found cannabinoids superior to placebo for CINV prevention but no advantage over active comparators, with nearly all studies predating modern antiemetic regimens.
Oncologists, palliative care specialists, pharmacists managing CINV
Cannabinoids were 2.65x more effective than placebo, but 23 of 26 trials predate 2000
What the researchers found
Cannabinoids superior to placebo for overall CINV control (RR 2.65, 95% CI 1.70-4.12); no difference vs active comparators; 23 of 26 studies published before 2000; one recent trial showed THC:CBD promise as adjunctive therapy.
Why it matters
Despite decades of interest, almost all evidence predates modern antiemetic protocols, leaving a critical gap for current oncology practice.
The numbers in context
26 RCTs; 23 before 2000; cannabinoids vs placebo RR 2.65 (1.70-4.12, I2=0%); no difference vs active comparators; nearly half had bias concerns.
How the study worked
Systematic review and meta-analysis of 26 RCTs from inception to March 2024; random effects meta-analysis by endpoint; subgroup analyses by control and design.
What this study cannot tell us
23 of 26 studies pre-2000 with dated comparators; heterogeneous designs; insufficient evidence for modern adjunctive use including olanzapine.
How to read the evidence
Clear placebo superiority but nearly all evidence predates current standard of care, severely limiting applicability.
When this study was published
Published 2025, search through March 2024
The bigger picture
The cannabis-for-chemo-nausea narrative is based on decades-old trials. Whether cannabinoids add value to modern triple/quadruple regimens remains unanswered.
Questions still open
- Does THC:CBD add benefit when olanzapine is included? Are pre-2000 results still relevant? What trial designs are needed?
Common questions
Do cannabinoids help with chemo nausea?
Should oncologists prescribe cannabinoids for nausea?
Read the original research
Efficacy of cannabinoids for the prophylaxis of chemotherapy-induced nausea and vomiting-a systematic review and meta-analysis.
Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer, 33(3), 193
Citation
Chow, Ronald; Basu, Anna; Kaur, Jagdeep; Hui, David; Im, James; Prsic, Elizabeth; Boldt, Gabriel; Lock, Michael; Eng, Lawson; Ng, Terry L; Zimmermann, Camilla; Scotte, Florian. (2025). Efficacy of cannabinoids for the prophylaxis of chemotherapy-induced nausea and vomiting-a systematic review and meta-analysis.. Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer, 33(3), 193. https://doi.org/10.1007/s00520-025-09251-w
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