CDC: ER Visits for Cannabis Hyperemesis Syndrome Up 3.7-Fold

What the CDC looked at

CDC researchers analyzed emergency department data from the National Syndromic Surveillance Program, covering 3,636 facilities from January 2023 to May 2026. Out of more than 407 million ER visits in that period, 199,565 involved cannabis hyperemesis syndrome (CHS).

The key change came on October 1, 2025. Before that date, there was no specific diagnosis code for CHS. Doctors had to combine a general code for vomiting with a code for cannabis use, and many cases were probably never labeled as CHS at all. Since October 2025, the syndrome has its own code (ICD-10-CM R11.16).

The numbers

• Before the new code, about 3.2 of every 10,000 ER visits involved CHS. That rate stayed fairly steady from 2023 into September 2025.
• In October 2025, the first month with the new code, it jumped to 11.26 per 10,000.
• From October 2025 to May 2026, it averaged 11.97 per 10,000. That is 3.7 times the average before the code.
• Young people were hit hardest. Among 15 to 24 year olds, the rate went from 9.99 to 38.70 per 10,000 ER visits.
• After the new code, the rate was slightly higher in women (12.65) than in men (11.13).

What the numbers do not show

The authors state plainly that the jump at least partly reflects better recognition and coding, not a sudden rise in how many people actually have the syndrome. A new code makes a condition easier to record, so the October spike is partly a counting effect.

The report also only covers people who were sick enough to go to an emergency room. Cannabis use was based on what patients said, and the reporting hospitals may not represent the whole country. Anyone who rode out the vomiting at home does not appear in these figures.

Read the other way around, though, the data says something uncomfortable: for years, a large share of CHS cases likely went unrecognized. The true number of people dealing with it was probably always higher than the old statistics suggested.

What CHS is

The CDC describes cannabis hyperemesis syndrome as sudden episodes of severe nausea, vomiting and abdominal pain in people who use cannabis regularly over a long time. Many people who have it describe the same pattern: episodes that come back, and a strong urge to take hot showers or baths because they bring short relief.

According to the report, outcomes range from symptoms going away after a person stops using cannabis to, in rare cases, death. The CDC calls on doctors to think of CHS when patients come in with these symptoms and to ask about how often, how long and in what form they use cannabis.

Why it matters if you use every day

CHS is not something that only happens to other people. It shows up after long, regular use, which describes many daily users. One reason it goes unnoticed for so long: plenty of people use cannabis to calm their stomach, so when the nausea gets worse, they use more. That keeps the cycle going.

A doctor quoted by WILX at University of Michigan Health said CHS is now the most common cannabis-related diagnosis in the ER and pointed to today’s much stronger THC products as one likely factor. That view is his, not part of the CDC analysis, but it fits what many users describe.

If you keep getting morning nausea, vomiting spells or stomach cramps, and hot showers are the only thing that helps, take it seriously. Tell your doctor how much you use, honestly. The one thing that reliably ends the syndrome is stopping cannabis.

What you can do now

• Keep a short log for two weeks: how much you use, and when the nausea or vomiting shows up.
• If you have had more than one episode, talk to a doctor and mention cannabis directly. Without that detail, CHS is easy to miss.
• If you have tried to cut back and could not, that is not a lack of willpower. It is a sign that you may need a plan and some support to quit.

Sources

Vivolo-Kantor AM et al., “Trends in Emergency Department Visits Involving Cannabis Hyperemesis Syndrome Identified Using a New Diagnosis Code, United States, January 2023 to May 2026,” MMWR 2026;75(30):391 to 396, published August 6, 2026, read the report on cdc.gov. Reported again by WILX on November 2, 2026.