Cannabis hyperemesis syndrome, a severe vomiting condition tied to long-term marijuana use, was recently given its own diagnostic code by the World Health Organization, a change that took effect in October and has been picked up by U.S. health agencies. That move makes it easier for doctors to identify and track the disorder, which has been rising alongside wider access to high-potency cannabis products. Medical teams and researchers hope better data will reveal patterns and help clinicians treat patients who often arrive at emergency rooms confused and critically dehydrated. The recognition also shines a light on why some people suffer repeated, intense bouts of nausea and vomiting linked to chronic cannabis exposure.
The WHO’s update means CHS is no longer hidden inside generic vomiting or gastrointestinal categories, so clinicians can finally log cases under a specific label and flag trends. For emergency departments, that clarity matters because it can change treatment priorities and follow-up care. Hospitals that already tracked CHS say having an official code will standardize reporting and make comparisons between regions possible.
CHS is not a mild upset stomach; it produces relentless nausea, stomach pain, repeated vomiting and severe dehydration that sometimes leads to weight loss and organ stress. Patients report an especially distressing symptom called “scromiting” — screaming and vomiting at the same time due to extreme pain, according to the Cleveland Clinic. In rare situations, complications can include heart rhythm problems, seizures, kidney failure and even death when dehydration and electrolyte imbalances are extreme.
Clinicians have long struggled because CHS looks like other common illnesses, such as food poisoning or the stomach flu, and many people go without a diagnosis for months or years. “It helps us count and monitor these cases,” said Beatriz Carlini, a research associate professor at the University of Washington School of Medicine. “A new code for cannabis hyperemesis syndrome will supply important hard evidence on cannabis-adverse events, which physicians tell us is a growing problem,” added Carlini, who studies adverse health effects of cannabis use.
Recent research shows emergency department visits for CHS surged during the COVID-19 pandemic and have stayed elevated, with stress, isolation and more potent cannabis products suspected as contributing factors. One large analysis noted a roughly 650% increase in CHS-related ER visits from 2016 up through the pandemic peak, with the biggest impact among adults ages 18 to 35. Researchers also point out that the typical THC concentrations in available products have climbed dramatically over the past few decades.
Clinicians and addiction specialists are seeing a clear pattern in who gets sick: long-term, frequent users exposed to much stronger cannabis than earlier generations experienced. “In my opinion, and the research also supports this, the increased rates of CHS are absolutely linked to high-potency cannabis — often products are over 90% THC,” Puls told Fox News Digital. That connection is a leading hypothesis, even as scientists continue to study why a drug known to reduce nausea can, in some chronic users, produce the opposite effect.
Researchers propose that heavy, prolonged cannabis use may overstimulate the body’s cannabinoid receptors and flip the normal anti-nausea response into one that triggers vomiting instead. “Although cannabis can be used to treat nausea, those products are typically much lower dose THC — usually less than 5%,” Puls said. The theory helps explain why people who used low-dose cannabis therapeutically in the past might still develop CHS after switching to modern high-potency products.
A peculiar feature of CHS is that sufferers often find temporary relief only by taking long, hot showers, a behavior that makes the condition striking and sometimes misleading. Because the syndrome comes and goes, many users assume a single episode was an isolated illness and continue using cannabis until the next severe attack. Addiction and dependence complicate cessation efforts, which means even diagnosed patients sometimes struggle to quit despite repeated episodes.
“Some people say they’ve used cannabis without a problem for decades,” said Dr. Chris Buresh, an emergency medicine specialist with UW Medicine. Once a person has experienced CHS, they are more likely to have further episodes, and that recurrence is a major reason clinicians want better surveillance. “My hope would be that with this new diagnosis code that CHS is more accurately diagnosed in an emergency room setting,” he said, which could lead to clearer guidance for both patients and providers.
Public health experts expect the new code to improve tracking and reveal geographic and demographic trends as legalization and high-potency products expand. Better data should also make it easier to study prevention strategies and to communicate risks to populations most affected by CHS. Clinicians will watch for how reporting changes now that the syndrome has an official place in diagnostic manuals, and researchers will use the new coding to dig deeper into causes and outcomes.
