A new California study is raising alarms about a possible link between cannabis vaping and a rare but potentially deadly condition that can leave users violently ill for days.
The study, published in the journal Cannabis and Cannabinoid Research, found that people who used electronic vape cartridges developed cannabinoid hyperemesis syndrome (CHS) significantly faster than those who smoked marijuana or consumed edibles. CHS is a condition that causes cycles of severe nausea, stomach pain, and extreme vomiting in long-term cannabis users.
Megan Mbengue, one of the study’s authors, described the findings as alarming, especially given how popular vaping has become. “According to our recent study findings, those who utilize vapes alone are hitting it more often throughout the day and developing CHS symptoms sooner than those who smoke — by YEARS,” Mbengue wrote in a LinkedIn post, calling the trend “a massive public health concern.”
The study was based on more than 1,130 responses to a digital survey of people who reported experiencing CHS. It did not prove a direct cause-and-effect relationship between vaping and CHS, but it did find a strong statistical association. Vape cartridge users were more likely to develop CHS sooner and to use higher amounts of cannabis overall.
Lead author Codi Peterson, an associate professor of pharmaceutical sciences at UC Irvine, urged caution when interpreting the results. “This is just an association that we saw. We certainly can’t say anything definitive,” Peterson told SFGATE. “It’s just something we noticed that people who exclusively vaped developed CHS in a shorter timeline.”
The survey found that 96.5% of respondents used cannabis at least daily before developing CHS, and nearly half said they used it six or more times a day. Some had used cannabis for up to a decade before symptoms appeared.
CHS was first reported in 2004 and wasn’t officially defined with diagnostic criteria until 2016. Its symptoms include severe stomach pain, diarrhea, and an extreme form of vomiting sometimes called “scromiting” — a term combining “screaming” and “vomiting” — because those affected sometimes scream in pain while being sick. Many people with CHS take long, hot baths or showers to temporarily ease the nausea. At least three deaths have been linked to the syndrome.
According to the Cleveland Clinic, the only known cure for CHS is to stop using cannabis entirely. There are currently no therapies approved by the U.S. Food and Drug Administration (FDA) for the condition, though researchers are actively studying treatment options. Stopping cannabis use typically leads to symptom relief within 10 days, though full recovery can take months.
Scientists believe CHS may result from long-term overstimulation of receptors in the body’s endocannabinoid system (ECS) — a complex neurological network involved in controlling nausea and vomiting. Peterson said the heavy daily use documented in the survey, particularly with THC-rich vape cartridges, points strongly to THC itself as the likely culprit.
Some cannabis users have disputed that THC causes CHS, arguing instead that pesticide contamination or other toxins in cannabis products are responsible. But Peterson pushed back on that theory. “If it is just tainted weed, then everyone who bought from that one dealer or that store would get sick, yet only some people are getting sick,” he said. The study included respondents who purchased cannabis from both legal stores and unlicensed sources, which Peterson said further undermines the contamination argument.
CHS cases rose sharply across the country during the pandemic, according to a 2025 study examining emergency room visits between 2016 and 2022. Peterson said his goal is not to discourage cannabis use, but to give users better information. “It’s a little bit demeaning to tell someone how they should use this plant,” he said. “But if we teach people that this happens and there’s science behind it, then we can help more people.”
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