Cannabinoid Hyperemesis Syndrome: When Marijuana Causes the Vomiting It Usually Prevents | Research

The takeaway

Long-term marijuana use can paradoxically cause severe recurrent vomiting known as cannabinoid hyperemesis syndrome, a condition often misdiagnosed and treated with unnecessary tests and procedures.

Read this if you experience recurrent nausea or vomiting and use cannabis regularly.

Only proven treatment: complete cannabis cessation

What the researchers found

This clinical review described cannabinoid hyperemesis syndrome (CHS), a paradoxical condition where chronic marijuana use causes recurrent severe nausea and vomiting despite cannabis being known as an antiemetic.

The syndrome typically presents with cyclic episodes of vomiting, often accompanied by compulsive hot bathing (which temporarily relieves symptoms). Patients frequently undergo expensive and unnecessary investigations before the diagnosis is recognized.

The only proven treatment is complete cessation of marijuana use. The review emphasized that recognizing CHS can prevent unnecessary medical and surgical interventions in patients presenting with recurrent vomiting of unknown cause.

Why it matters

CHS is increasingly recognized as cannabis use becomes more widespread. Many patients cycle through multiple emergency department visits and undergo extensive testing before the diagnosis is made, creating significant healthcare costs and patient suffering.

The numbers in context

Review summarized case report literature; typical presentation involves chronic marijuana use, cyclic vomiting episodes, and relief from hot bathing; only treatment is cannabis cessation

How the study worked

Clinical review article examining published case reports and literature on the pathophysiology, presentation, diagnosis, and management of cannabinoid hyperemesis syndrome.

What this study cannot tell us

Based primarily on case reports and clinical observations. The pathophysiology remains incompletely understood. Prevalence among chronic cannabis users is unknown.

How to read the evidence

Clinical review synthesizing case report literature. Describes an increasingly recognized clinical entity, though prevalence data and controlled studies are limited.

When this study was published

Published in 2015. CHS has since become much more widely recognized, and hot water bathing has been validated as a clinical clue.

The bigger picture

CHS challenges the simple narrative that cannabis is universally antiemetic. The condition demonstrates that the relationship between cannabinoids and the gastrointestinal system is more complex than commonly understood, with chronic use potentially reversing the acute antiemetic effect.

Questions still open

What determines which chronic users develop CHS? Is there a dose or duration threshold? Could genetic factors predict susceptibility? Do different cannabis products or cannabinoid profiles carry different risk?

Common questions

How can marijuana cause vomiting if it is also used to treat nausea?

Acute cannabis use activates CB1 receptors in the brain that suppress nausea. However, chronic heavy use may cause changes in the gut and thermoregulatory system that paradoxically trigger severe vomiting episodes. The exact mechanism is not fully understood.

Why do hot showers help with CHS?

One theory is that hot water corrects a thermoregulatory imbalance in the hypothalamus caused by chronic cannabinoid exposure. Another suggests that redirecting blood flow from the gut to the skin reduces vomiting. The relief is temporary and does not address the underlying cause.

Read the original research

Cannabinoid hyperemesis syndrome: Marijuana is both antiemetic and proemetic.

Cleveland Clinic journal of medicine, 82(7), 429-34

View on PubMed ↗Publisher’s paper ↗

Citation

Lu, Marvin Louis Roy Y; Agito, Markus D. (2015). Cannabinoid hyperemesis syndrome: Marijuana is both antiemetic and proemetic.. Cleveland Clinic journal of medicine, 82(7), 429-34. https://doi.org/10.3949/ccjm.82a.14023