Some people have described a bizarre side effect after using marijuana: uncontrollable vomiting.

It’s sometimes called “scromiting” — a mash-up of screaming (from intense pain) and vomiting. The medical term is cannabis hyperemesis syndrome, a condition that can affect long-term, frequent cannabis users. Here’s what to know about the condition, its cause and who’s at risk.

What is cannabis hyperemesis syndrome?

Cannabis hyperemesis syndrome is a gastrointestinal condition in which people experience cycles of nausea, vomiting and abdominal pain after using cannabis.

Clinicians first named the syndrome in 2004 after over a dozen cannabis users in southern Australia sought medical care for repeated vomiting. A curious observation made at the time was that hot showers, or baths, appeared to make people feel better, the researchers reported.

Cannabis hyperemesis syndrome unfolds in phases. During the first couple of months, people may feel the urge to vomit, nausea in the morning and abdominal discomfort. Symptoms can progress to severe, persistent nausea and vomiting — known as hyperemesis — along with pain that usually starts at the top of the abdomen but later moves throughout it. This phase can last for several days and can be debilitating, with vomiting and dry heaving up to five times an hour and requiring emergency room visits.

Symptoms can be managed with intravenous fluids for dehydration and medications to help with nausea and pain. The only cure is to stop using marijuana, according to Cedars-Sinai Medical Center in Los Angeles.

What causes cannabis hyperemesis syndrome?

Cannabis contains over a hundred chemicals known as cannabinoids. Two of these are tetrahydrocannabinol, or THC, the compound known for causing feelings of euphoria and relaxation, and CBD, which has no psychoactive effect. These chemicals can interact with the endocannabinoid system, a molecular network found throughout the body that supports homeostasis, or biological balance.

At low doses, cannabis can help regulate nausea and chronic pain. In cannabis hyperemesis syndrome, researchers believe higher and repeated doses of cannabis push the endocannabinoid system too far, triggering nausea, vomiting and relentless abdominal pain, according to Johns Hopkins All Children’s Hospital in Florida.

Some research also suggests cannabis may interfere with the body’s ability to regulate temperature. That disruption may explain why people find temporary relief taking hot showers or baths.

Who gets cannabis hyperemesis syndrome?

People most at risk for cannabis hyperemesis syndrome are long-term users who use cannabis once or several times a day. Symptoms typically show up after 10 to 12 years of chronic use, according to Cedars-Sinai.

Higher rates of the condition have been reported among cigarette smokers, people who start using cannabis before age 16 and those with other substance use disorders.

While the prevalence of cannabis hyperemesis syndrome is unknown, it was considered rare but seems to be on the rise, according to some studies.

A 2024 study looking at health records from California found the annual prevalence of this condition increased by 134% to 175% over an 11-year period. And a 2020 study nearly one in five people hospitalized in the United States between 2005 and 2014 for cyclical vomiting syndrome, a broader diagnosis that includes cannabis hyperemesis syndrome, reported using cannabis at the time. The researchers reported this prevalence was significantly greater over the last decade, possibly due to changing legislation around cannabis and more people using it.

Miriam Fauzia is a science reporting fellow at The Dallas Morning News. Her fellowship is supported by the University of Texas at Dallas. The News makes all editorial decisions.