States that have legalized recreational marijuana are experienced rising levels of emergency room visits for cannabinoid hyperemesis syndrome

Emergency departments across the country are seeing a sharp rise in cannabinoid hyperemesis syndrome (CHS), and new reporting from The Hill underscores how legalization trends appear to be accelerating the problem. CHS-first identified in Australia more than two decades ago-is a paradoxical condition in which long‑term, heavy cannabis use triggers cycles of severe nausea, abdominal pain, and uncontrollable vomiting. As more states expand access to marijuana, clinicians are documenting a surge in patients arriving at hospitals with symptoms that can be debilitating and, in some cases, dangerous.

Rising Emergency Department Visits

Multiple states that have legalized marijuana in recent years are reporting significant increases in CHS‑related emergency visits. A 2025 study cited by The Hill found that CHS diagnoses rose from 4.4 per 100,000 emergency department visits in 2016 to 33.1 per 100,000 in 2020, before settling at 22.3 per 100,000 in 2022.

Virginia offers one of the clearest examples of this trend. Emergency department visits for CHS there have climbed nearly 29% since 2020, according to statewide hospital data. Similar spikes have been documented in Massachusetts, Northern California, and parts of North Carolina, where clinicians report seeing CHS patients "every week, if not every day."

These increases align with broader national patterns. Millions of Americans now use cannabis daily, and researchers estimate that more than 2.75 million people may experience CHS symptoms.

What CHS Looks Like in the ER

CHS typically affects people who have used cannabis heavily-often daily for years. Symptoms tend to follow a pattern:

- Severe, unrelenting nausea

- Repeated vomiting, sometimes dozens of times per hour

- Intense abdominal pain

- Morning symptom peaks

- Temporary relief from hot showers or baths

Clinicians in Colorado, one of the earliest states to legalize cannabis, report seeing CHS patients multiple times a week, with some cases severe enough to cause kidney failure or esophageal tears from forceful vomiting.

Because CHS mimics other gastrointestinal disorders, patients are often misdiagnosed with cyclic vomiting syndrome or food‑borne illness. The World Health Organization's decision in October to add CHS to its diagnostic manual is expected to improve reporting and recognition.

Why Legalization Is Linked to Rising Cases

Researchers and clinicians point to several factors connecting legalization to increased CHS cases:

- Higher potency products: Modern cannabis strains and concentrates contain far more THC than those available decades ago, increasing the risk of overstimulation of cannabinoid receptors.

- Greater availability: Legal markets make cannabis easier to obtain, often in forms that encourage frequent use.

- Daily or near‑daily consumption: Studies show that more than 40% of CHS patients use cannabis five or more times a day, and many have used it heavily for five years or longer.

- Delayed recognition: As awareness grows, more clinicians are identifying CHS correctly, contributing to the rise in documented cases.

States that legalized earlier-such as Colorado and California-were among the first to report surges, and newer legal states are now seeing similar patterns.

Who Is Most Affected?

Data suggest that CHS disproportionately affects:

- Young adults, especially those ages 18–34

- Hispanic and Black individuals, according to a Massachusetts study

- People with long‑term, heavy cannabis use patterns

These demographics overlap with groups most likely to use high‑potency cannabis products regularly.

Treatment and Challenges for Hospitals

Treating CHS in the emergency setting is difficult. Standard anti‑nausea medications often fail, leaving clinicians to rely on:

- IV fluids for dehydration

- Pain management

- Hot showers, which many patients report as the only immediate relief

- Benzodiazepines in some cases to reduce anxiety and vomiting

But the only known cure is stopping cannabis use entirely.

For hospitals, CHS adds strain to already busy emergency departments. Recurrent visits are common, and patients often undergo extensive testing before receiving a correct diagnosis.

A Growing Public Health Concern

As legalization expands and cannabis potency continues to rise, CHS is emerging as a significant-and often overlooked-public health issue. Emergency physicians warn that without broader awareness, more patients will suffer repeated, severe episodes before recognizing the connection to their cannabis use.

The Hill's reporting highlights a trend that states, clinicians, and public health agencies will need to confront: legalization brings benefits and economic opportunities, but it also introduces new medical challenges that require education, research, and clear communication to the public.