CDC Report Finds ER Visits for Cannabis Hyperemesis Syndrome Jumped 16% After New Diagnosis Code Took Effect

The CDC released a report Thursday, August 6, showing emergency room diagnoses of cannabis hyperemesis syndrome jumped 16% from October 2025 through May 2026. The report, published in the CDC's Morbidity and Mortality Weekly Report and covered by Newsday, comes from the agency's National Center for Injury Prevention and Control. Researchers Alana Vivolo-Kantor, Stephen Liu, Lauren Tanz, Christine Mattson, and Josh Schier analyzed data from roughly 7,500 healthcare facilities nationwide.

What the Syndrome Actually Is

Cannabis hyperemesis syndrome, or CHS, hits frequent marijuana users, especially smokers, with cyclical bouts of nausea, uncontrollable vomiting, and severe abdominal pain. Past research cited in the CDC report estimated 2.75 million Americans suffer from it every year.

From January 2023 through May 2026, the CDC counted 199,565 ER visits tied to CHS. That's not a small number. But the timeline matters more than the total.

The Code Change Is the Real Story

The key detail: the proportion of ER visits involving CHS stayed mostly flat from January 2023 through September 2025. Then, on October 1, 2025, a new CHS-specific diagnosis code went into effect under the International Classification of Diseases system. The very next month, diagnoses spiked.

Before that code existed, doctors had to piece together a CHS diagnosis by combining separate codes for nausea, vomiting, and cannabis use. That's clunky. It means a lot of CHS cases were probably getting missed, misfiled under generic stomach bugs, or blamed on something else entirely.

Vivolo-Kantor told Newsday that "the abruptness and sustained magnitude of the increase" traces mainly to that new code giving doctors a cleaner, more accurate way to log what they're actually seeing. This isn't necessarily more people getting sick. It's more doctors correctly writing down what's already been happening.

Who's Showing Up in ERs

The demographic breakdown is where things get more interesting. The CDC found the largest increases hit people aged 15 to 24, teenage girls and women, and Black Americans along with American Indian and Alaska Native patients.

The youth numbers surprised the CDC's own researchers. Vivolo-Kantor told Newsday the assumption going in was that chronic, heavy cannabis use, the kind that typically triggers CHS, takes years to develop. Seeing it show up so heavily in 15-to-24-year-olds raises an obvious question: how early are these kids starting, and with what products?

That question doesn't have a clean answer yet. The report itself calls for more research into how high-potency THC products, plus newer hemp-derived items like vapes, drinks, and gummies, are affecting younger users specifically. Those products didn't exist in their current potency and packaging a decade ago, and the CDC hasn't nailed down exactly how they factor into CHS rates among teenagers.

The Coding Argument

Someone skeptical of treating this as a genuine public health alarm has a reasonable point: if the entire spike lines up with a coding change, you can't cleanly separate "more diagnoses" from "more disease." The CDC report itself acknowledges this directly, stating the new code "has improved CHS surveillance" precisely because the condition was likely underestimated before. That's the researchers' own framing.

Where that skepticism runs out of road is the demographic pattern. A coding fix should improve accuracy roughly evenly across age groups. Instead, the sharpest jumps concentrated in teens and young adults specifically, which suggests something real is happening in how younger people are using cannabis products, not just how billing codes work.

What Comes Next

The CDC says more research is needed on high-potency and hemp-derived products, especially their marketing to and use by younger Americans. No new federal policy or regulatory action was announced alongside this report. The immediate practical takeaway from the agency: doctors treating young patients with unexplained cyclical vomiting should start asking about cannabis use, given how easily this condition slipped past diagnosis for years.