Phytocannabinoids, particularly those derived from cannabis such as delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), have scientific evidence supporting their use in the management of nausea and vomiting, especially when these symptoms are induced by chemotherapy. Several randomized controlled trials and systematic reviews have demonstrated that cannabinoids can be effective antiemetic agents, often outperforming some conventional antiemetic medications in certain patient populations. The mechanism of action is primarily attributed to the interaction of phytocannabinoids with the endocannabinoid system, particularly the CB1 receptors in the central nervous system, which play a role in regulating nausea and vomiting.

Clinical guidelines in some countries, such as Canada, recognize the use of synthetic cannabinoids (e.g., dronabinol and nabilone, which mimic phytocannabinoids) for chemotherapy-induced nausea and vomiting that is refractory to standard therapies. The U.S. Food and Drug Administration (FDA) has also approved certain synthetic cannabinoids for this indication, lending further credence to their efficacy. However, it should be noted that the evidence is strongest for specific, well-characterized phytocannabinoids and may not apply to all cannabinoids or cannabis products. Common side effects include dizziness, sedation, and euphoria, which may limit use in some patients. Overall, there is substantial scientific validation for the use of certain phytocannabinoids in treating nausea and vomiting, particularly in the context of cancer therapy.