Cannabinoid Hyperemesis Syndrome (CHS): What Is It?

Cannabinoid hyperemesis syndrome (CHS) involves recurring episodes of severe nausea, vomiting and often abdominal pain associated with cannabis use. It is most often recognized in people with frequent, prolonged use, but a person does not need to fit one stereotyped profile to need evaluation. Sustained cannabis cessation is central to preventing recurrence.

Seek urgent medical care if repeated vomiting prevents you from keeping fluids down. Fainting, confusion, very little urine or other signs of severe dehydration warrant emergency care. Do not assume that vomiting is CHS merely because you use cannabis.

Recognizing the Pattern

Symptoms may include a period of morning nausea or abdominal discomfort, followed by an episode of intense vomiting and then a period of improvement. Episodes can recur, with relatively well intervals between them. Some people use more cannabis because it seems to relieve nausea temporarily, which can make the relationship difficult to recognize.

Hot showers or baths can provide temporary relief for some patients. That behavior is not required for diagnosis and does not uniquely identify CHS. Repeated or excessively hot bathing can cause burns and worsen dehydration; it is not a cure. Cleveland Clinic’s patient guidance describes these complications and signs requiring emergency assessment.

What New Surveillance Adds

An August 2026 CDC report examined emergency department visits through May 2026. A CHS-specific diagnostic code introduced in October 2025 identified substantially more visits than the older coding approach. The abrupt increase likely reflected improved recognition and coding at least in part, rather than an immediate jump of the same size in the underlying condition.

The report also highlighted younger age groups and noted that symptoms can begin sooner than older descriptions suggested, including within the first year of use. Emergency department statistics are not the percentage of all cannabis users who develop CHS. Its population prevalence remains difficult to measure.

Why CHS Happens Is Still Uncertain

Researchers are investigating how repeated cannabinoid exposure affects pathways controlling nausea, gut function and temperature regulation. These are possible mechanisms, not a settled explanation or a laboratory test that can prove CHS in an individual.

The apparent contradiction is real: cannabis can temporarily reduce nausea in some circumstances while contributing to recurrent vomiting in CHS. Temporary relief after using cannabis does not rule out the syndrome.

How Clinicians Evaluate It

The American Gastroenterological Association’s 2024 clinical update describes a typical pattern of at least three vomiting episodes annually, cannabis use averaging more than four times weekly for over a year before symptoms, and sustained resolution after stopping. These clinical criteria help assessment; they should not delay care for someone with a shorter history or an atypical presentation.

The AGA describes documenting resolution over at least six months of abstinence, or a period spanning three typical vomiting cycles. This is a follow-up framework for confirming the pattern, not a claim that every patient must remain acutely ill for six months.

There is no single diagnostic blood test. Clinicians consider cannabis and other substance use, medications, symptom timing and examination findings, then order tests as appropriate. Dehydration, electrolyte disturbances and kidney injury need assessment. Other explanations can include infection, obstruction, pregnancy-related vomiting, metabolic disease and cyclic vomiting syndrome.

Tell the care team about flower, vapes, concentrates, edibles and other cannabinoid products, including frequency and recent changes. Accurate information helps treatment; respectful care should not depend on whether a patient has already managed to stop.

Treating an Acute Episode

Treatment may include intravenous fluids, correction of electrolyte abnormalities and medication for symptoms. Common anti-nausea drugs do not always work well for CHS. The Royal College of Emergency Medicine guideline discusses clinician-directed haloperidol and topical capsaicin among options when appropriate.

These are not instructions for unsupervised treatment. Clinicians must consider medication interactions, adverse effects and monitoring needs. Capsaicin can irritate skin, and relief from an acute treatment does not prevent another episode if the underlying trigger continues.

Recovery and Preventing Recurrence

The 2025 European guideline on chronic nausea and vomiting identifies cannabis withdrawal from use as the most effective treatment for CHS. Recovery time varies, and follow-up helps distinguish improvement from a temporary symptom-free interval. Resuming cannabis can bring episodes back.

Changing strain, switching from smoking to edibles, or simply lowering THC is not an established substitute for cessation. Discuss all cannabinoid products with the treating clinician rather than assuming a different label solves the problem.

Stopping can be difficult, particularly when cannabis has been used for symptoms or when dependence is present. Support can include counseling, management of withdrawal symptoms and a plan for the original reason for use. Difficulty stopping is not a failure of willpower. Our guide to recognizing problematic use can help start that conversation.

Repeated vomiting deserves medical attention, even after a previous CHS diagnosis. A clear follow-up plan and practical support for sustained cessation are more useful than relying on hot showers or repeatedly treating episodes in isolation.