How cannabinoids control nausea and vomiting in the body

What the researchers found

This review pulled together decades of research on how the endocannabinoid system regulates nausea and vomiting. CB1 receptor activation consistently suppressed vomiting across multiple animal species, while CB1 inverse agonists (like rimonabant) actually promoted it.

CBD showed anti-nausea effects within a limited dose range, apparently working through serotonin 5-HT1A receptors in the brainstem rather than cannabinoid receptors directly. This is a different mechanism than THC uses.

Animal research suggested cannabinoids may be particularly effective against anticipatory nausea, the type that develops when patients begin to feel sick before chemotherapy even starts. This form of nausea responds poorly to standard anti-emetic drugs.

Why it matters

Standard anti-nausea medications work well for acute chemotherapy-induced vomiting but perform poorly against anticipatory nausea. This review identified cannabinoids as a potential tool for that gap, with CBD offering a non-intoxicating option.

The numbers in context

CB1 agonists suppressed conditioned gaping (nausea proxy) in rats. CBD was effective within a limited dose range. FAAH inhibitor URB-597 also suppressed nausea responses.

How the study worked

This was a narrative review synthesizing preclinical and clinical evidence on cannabinoid regulation of nausea and vomiting. The authors examined studies across emetic species (ferrets, shrews) and rodent models using conditioned gaping reactions as a proxy for nausea.

What this study cannot tell us

Much of the evidence came from animal models. Rats and mice cannot vomit, so researchers used conditioned gaping as a proxy for nausea, which may not perfectly translate to human experience. Clinical trial data in humans was limited at the time of review.

How to read the evidence

Narrative review synthesizing animal and limited clinical evidence. Provides mechanistic understanding but relies heavily on preclinical models.

When this study was published

Published in 2011. CBD anti-nausea research has expanded considerably since this review.

The bigger picture

The distinction between THC and CBD mechanisms matters for drug development. CBD working through serotonin receptors means it could potentially be combined with existing anti-emetics that target different pathways, without the psychoactive effects of THC.

Questions still open

• What is the optimal CBD dose range for nausea in humans? Can CBD be combined with standard anti-emetics for better results? Why does CBD lose effectiveness outside its limited dose window?

Common questions

Read the original research

Regulation of nausea and vomiting by cannabinoids.

British journal of pharmacology, 163(7), 1411-22

Citation

Parker, Linda A; Rock, Erin M; Limebeer, Cheryl L. (2011). Regulation of nausea and vomiting by cannabinoids.. British journal of pharmacology, 163(7), 1411-22. https://doi.org/10.1111/j.1476-5381.2010.01176.x

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