US sees a big jump in nausea cases among frequent marijuana users in the hospital

The U.S. has witnessed a significant rise in hospital admissions of frequent marijuana users suffering from nausea and vomiting, according to a recent report by the U.S. Centers for Disease Control and Prevention (CDC). The abrupt and substantial increase is largely attributed to the introduction of a new diagnosis code last fall, which has shed light on this previously underrecognized issue.

Emergency room diagnoses of the condition, known as cannabis hyperemesis syndrome, surged by 16% from October 2023 to May 2025, as per federal researchers. This syndrome affects individuals who frequently use marijuana, particularly those who smoke it, and is characterized by recurring nausea, uncontrollable vomiting, and severe abdominal pain.

While past research has estimated that around 2.75 million Americans annually suffer from this condition, hospital emergency room visits related to it have been on the rise as daily recreational marijuana use has increased. However, experts have also pointed out that the syndrome has likely been widely underdiagnosed, possibly due to doctors' lack of understanding of patients' marijuana use or their attributing the symptoms to other medical conditions.

To track the syndrome, researchers combined diagnostic codes for nausea and vomiting with codes for cannabis use. The CDC's National Center for Injury Prevention and Control analyzed emergency room data from approximately 7,500 healthcare facilities nationwide through May 2025. From January 2023 to the summer of 2025, nearly 200,000 syndrome-related visits were recorded in emergency departments.