After implementing a new diagnostic code, the CDC found monthly proportions of emergency department visits for cannabis hyperemesis syndrome was 3.7 times higher between October 2025 and May 2026 compared to visits between January 2023 and September 2025.
Cannabis hyperemesis syndrome is a syndrome attributed to prolonged, frequent cannabis use and includes symptoms such as severe nausea, vomiting and abdominal pain. On Oct. 1, the CDC implemented a new diagnostic code for CHS, and the results suggest that the code has improved recognition and detection of a previously underestimated condition, according to an Aug. 6 CDC news release.
For the study, the CDC used its National Syndromic Surveillance Program and analyzed data from 3,636 ED facilities that consistently reported data from Jan. 1, 2023, through May 31, 2026.
Here is what to know.
1. Between January 2023 and May 2026, there were 199,565 ED visits involving CHS, and the proportion of ED visits for CHS remained mostly steady until the new code implementation in October.
2. In the first month after the code implementation, the proportion of CHS-involved ED visits increased from 3.35 per 10,000 ED visits in September 2025 to 11.26 per 10,000 ED visits in October 2025.
3. Higher proportions of monthly CHS-involved ED visits were seen among people ages 15-24 at a rate of 38.7 per 10,000 ED visits, females at a rate of 12.65 and Black persons at a rate of 17.6.
“The new CHS-specific diagnosis code has improved CHS surveillance and estimation of public health impact,” the release said. “However, increased clinical recognition and education about risks of frequent cannabis use are still needed, particularly in younger populations.”
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