Cannabis hyperemesis syndrome, a condition of repeated vomiting and severe stomach pain in frequent cannabis users, is showing up more often in emergency rooms, according to a CDC report covered by the Associated Press in August. The harder question is how much of the increase is more illness and how much is better counting.
CDC researchers counted a 16% rise in emergency diagnoses from October 2025 to May 2026, but they say the jump is largely due to a new diagnosis code that makes the condition easier to count. The report’s surprise was age: the largest increases were among people 15 to 24. It does not show that cannabis hyperemesis syndrome has suddenly become 16% more common.
What Is Cannabis Hyperemesis Syndrome?
The syndrome appears in people who use cannabis frequently, especially smokers. As the AP described it, symptoms include recurring nausea, uncontrollable vomiting and severe abdominal pain. The AP cited earlier research, published in JAMA, that estimated about 2.75 million Americans experience it in a year.
What the CDC Report Found
| Finding | Detail as reported |
|---|---|
| Change in ER diagnoses | Up 16% from October 2025 through May 2026 |
| Data source | Emergency department records from about 7,500 facilities through May |
| Earlier volume | Almost 200,000 related ER visits from January 2023 through summer 2025 |
| Trend before October | Relatively flat, then a sharp jump when the new code took effect |
| Largest increases | Ages 15 to 24, teenage girls and women, Black Americans, and American Indian and Alaska Native people |
Why a Billing Code Changes the Story
Before October 2025, researchers had to infer cases by combining codes for nausea and vomiting with codes for cannabis use. A condition-specific code gives clinicians a direct way to record it. The report’s authors described “the abruptness and sustained magnitude of the increase” as largely due to that change, which they said provides a more accurate picture of an underrecognized problem. The AP did not report how much of the 16% the code alone explains.
That is a useful lesson for reading any health statistic: when the way something is counted changes, the trend line changes too, even if nothing happens in the real world.
The Age Finding Researchers Did Not Expect
CDC’s Alana Vivolo-Kantor, the report’s first author, told the AP the age pattern was “one of the surprising findings for us.” The working assumption had been that younger people would not have used cannabis long enough to develop the condition, which raises the question of how early the people affected began using. The authors also called for more research on newer high-potency THC and hemp-derived products, including vapes, drinks and gummies, and how they affect younger Americans.
What This Means for Adults Who Use Cannabis
- Know the pattern. Repeated episodes of nausea, vomiting and abdominal pain in someone who uses cannabis often are worth raising with a clinician, even if the cause seems like a stomach bug.
- Tell the emergency team about cannabis use. The report’s authors and outside experts note the condition is easy to miss when cannabis use is not mentioned. Honest answers help clinicians consider it.
- Do not self-treat severe vomiting. Persistent vomiting can lead to dehydration. The CDC report does not address treatment, so ask a clinician what applies to you.
- Mind frequency and potency. The condition is linked to frequent use. If cannabis is part of your routine, track how often and how strong; our dose-response review explains why potency matters.
- Parents and caregivers. The age findings are a reason for calm, direct conversations with teens and young adults about frequent use and high-potency products.
What We Still Do Not Know
The report covers emergency visits only, so it does not capture people treated elsewhere or who never sought care. It cannot separate more recognition from more illness. And it does not say which products, doses or frequencies carry the most risk. Until researchers answer those questions, the safest reading is the narrow one: the condition is real, it is being identified more often, and it is more common in younger people than experts expected. For related reading, see our explainers on cannabis use disorder and withdrawal and on cannabis and medication interactions, and browse the Research Desk.