Hospitals across the U.S. have experienced a substantial increase in emergency room visits for nausea and vomiting conditions among frequent marijuana users over the past year. This surge is attributed, in part, to the recent implementation of a specific diagnostic code for cannabis hyperemesis syndrome (CHS), which has improved the accuracy of tracking this previously underrecognized condition.
Federal researchers found that emergency room diagnoses of CHS rose by 16% from October of last year to May of this year. The syndrome, characterized by recurrent nausea, uncontrollable vomiting, and severe abdominal pain, primarily affects individuals who use marijuana frequently, especially through smoking.
Previous research estimated that approximately 2.75 million Americans suffer from CHS annually, with emergency room visits reportedly increasing alongside the rise in daily recreational marijuana use. Experts suggest that CHS has likely been underdiagnosed historically, possibly due to a lack of awareness among healthcare providers or misattribution of symptoms to other illnesses.
The new report, which analyzed emergency room data from about 7,500 healthcare facilities nationwide through May, identified nearly 200,000 syndrome-related visits from January 2023 through the summer of 2025. While the burden on ERs remained relatively stable for most of the study period, a notable increase occurred in October, coinciding with the introduction of the new diagnostic code.
The most significant increases in CHS diagnoses were observed in individuals aged 15 to 24, teenage girls and women, and among Black Americans and American Indian and Alaska Native populations. The rise in diagnoses among younger individuals was particularly surprising to researchers, who questioned how such young people could have developed chronic use patterns.
These findings highlight the need to enhance public awareness of CHS, particularly among adolescents and young adults. The report also calls for further research into the effects of newer, high-potency THC and hemp-derived products, such as vapes, drinks, and gummies, on younger populations.