University of Washington School of Medicine doctors have been observing a trend amongst some chronic cannabis users: stomach pain and prolonged or severe vomiting. These symptoms, which have been increasingly observed in emergency rooms according to UW Medicine, are now officially recognised as “cannabis hyperemesis syndrome.”
Dr. Chris Buresh, an emergency medicine specialist at UW Medicine and Seattle Children’s, noted, “It seems like we see a lot of people coming in with this nausea, and this vomiting. A lot of belly pain.” He added that as he and his colleagues would talk to patients, they often found that the patients experiencing these problems were regular cannabis users.
Cannabis hyperemesis syndrome is “a gut problem that starts within 24 hours of the most recent use and can last for days. Users experience symptoms cyclically three or four times a year,” according to UW Medicine.
The formal designation was recognised by the World Health Organization on 1 October. The WHO updated its International Classification of Diseases manual (ICD-10, currently) and standardised the new code, R11.16, which was also updated for US clinicians by the Centers for Disease Control and Prevention.
The formal recognition of cannabis hyperemesis syndrome will help addiction researchers collect data on the impacts of chronic cannabis use. Beatriz Carlini, a research associate professor at UW School of Medicine, Psychiatry and Behavioral Sciences Department, explained, “Now that we have a name, we can better educate society to understand that cannabis, yes, helps to control nausea in some people. It’s very helpful for some people. But the other side is the opposite. They also can provoke very painful vomit with a lot of stress.”
Dr. Buresh mentioned that a hot shower is one of the few treatments known to alleviate the symptoms of cannabis hyperemesis syndrome. UW Medicine indicated “one over-the-counter treatment that may ease symptoms is capsaicin cream, an analgesic that creates a sensation of heat.”
The formal recognition of cannabis hyperemesis syndrome by the World Health Organization and its incorporation into the International Classification of Diseases manual represents a significant milestone in documenting the adverse health effects associated with chronic cannabis use, providing medical professionals with standardised diagnostic criteria and enabling systematic data collection about a condition that has likely affected users for years without proper identification.
The syndrome’s paradoxical nature, where a substance widely recognised for anti-nausea properties in some contexts instead triggers severe nausea and vomiting in chronic users, challenges common assumptions about cannabis as a uniformly benign substance with primarily therapeutic effects. This complexity underscores the need for nuanced public health messaging that acknowledges both the legitimate medical applications of cannabis and the potential adverse effects that can emerge with heavy, prolonged use.
The cyclical pattern described by UW Medicine, where users experience symptoms three or four times annually beginning within 24 hours of most recent use and lasting for days, creates a distinctive clinical profile that helps differentiate cannabis hyperemesis syndrome from other gastrointestinal conditions. This episodic nature, combined with the temporal relationship to cannabis consumption, provides diagnostic clues that can guide clinicians toward proper identification when patients present with unexplained severe vomiting.
Dr. Buresh’s observation that emergency departments are seeing increasing numbers of patients with these symptoms reflects both the growing prevalence of chronic cannabis use following legalisation in Washington and other states, and potentially improved recognition of the syndrome by medical professionals who are beginning to ask specific questions about cannabis consumption patterns when evaluating patients with intractable vomiting.
The assignment of a specific ICD-10 code (R11.16) provides practical benefits beyond research data collection. Standardised diagnostic codes enable insurance billing, facilitate communication between healthcare providers, support quality improvement initiatives tracking condition prevalence and treatment outcomes, and allow public health agencies to monitor trends in cannabis-related health complications as legalisation expands.
