Cannabis Hyperemesis Syndrome (CHS) is a cyclical vomiting condition linked to chronic cannabis use that disproportionately affects young people and is frequently misdiagnosed. A 2025 narrative review consolidates available evidence on its clinical phases, treatment options, and the public health implications of rising THC potency, but the supporting data remain remarkably thin, resting primarily on case reports rather than controlled trials.

Emergency department visits for cyclical vomiting linked to cannabis use appear to be climbing, particularly in jurisdictions where legalization has broadened access to high-potency products. Adolescents and young adults are the demographic most frequently affected, yet surveys consistently show that both clinicians and cannabis users themselves have low awareness that CHS exists. This creates a diagnostic blind spot in primary care and emergency medicine, where patients may cycle through repeated costly workups for conditions that would resolve with cannabis cessation. Understanding the clinical presentation, differential diagnosis, and management of CHS is increasingly urgent for any provider caring for young people who use cannabis.

Cannabis Hyperemesis Syndrome is a condition characterized by recurrent episodes of severe nausea, vomiting, and abdominal pain in individuals who use cannabis chronically, often for months to years before symptom onset. The syndrome progresses through three recognized phases: a prodromal phase marked by early-morning nausea and abdominal discomfort that is frequently misattributed to other gastrointestinal conditions or eating disorders; a hyperemetic phase involving intense, cyclical vomiting with potential for serious dehydration and electrolyte disturbances; and a recovery phase in which symptoms resolve following sustained cannabis abstinence. The pathophysiology is thought to involve paradoxical effects of chronic cannabinoid receptor stimulation on the gut-brain axis, though the precise mechanisms remain poorly understood. A hallmark behavioral feature is compulsive hot-water bathing, which provides temporary symptom relief and serves as a key diagnostic clue.

This 2025 narrative review synthesized 13 primary studies, the majority of which were case reports and small case series, alongside one underpowered randomized controlled trial examining topical capsaicin. The review reports that THC potency has increased substantially over the past four decades, from approximately 3% in the 1980s to upward of 30% in some current products, and that a Canadian study found CHS-related emergency department visits rose significantly following legalization (incidence rate ratio 1.60, 95% CI 1.19 to 2.16). Cannabis abstinence remains the only reliably effective long-term treatment, while topical capsaicin shows promise for acute symptom relief. However, the authors acknowledge that the evidence supporting these recommendations is limited in both quantity and quality. They call for targeted education campaigns, prospective epidemiological studies, and further mechanistic research to fill the substantial gaps that currently prevent the development of evidence-based clinical guidelines for CHS in youth.

This review gets the big picture right: CHS is real, it is under-recognized, and it causes genuine suffering in patients who often have no idea their cannabis use is the culprit. The clinical descriptions of the three phases and the emphasis on compulsive hot bathing as a diagnostic red flag are clinically useful reminders. Where the review reaches further than the evidence allows is in implying that the public health crisis is well-quantified. In reality, we are working from a total evidence base that includes fewer than 30 adolescent patients across all published studies. The advocacy tone is understandable given the clinical stakes, but clinicians should recognize that definitive guidance simply does not exist yet.

In my own practice, I have seen CHS in patients ranging from occasional users of high-potency concentrates to daily flower users, and the presentation is often less textbook than reviews suggest. I always ask about hot bathing habits when evaluating recurrent vomiting in a cannabis user, and I have found that framing CHS as a receptor-level mismatch rather than a moral failing improves patient receptiveness. The most important clinical move is not prescribing capsaicin but rather having the conversation about a supervised cannabis taper or pause. That conversation requires trust, not judgment, and it often needs to happen more than once before a patient is ready to act on it.

This review sits very early in the research arc for CHS, consolidating what are essentially hypothesis-generating observations rather than confirmed findings. The field lacks prospective cohort studies that could clarify dose-response relationships, identify genetic or metabolic risk factors, or determine whether specific cannabinoid profiles (ratio of THC to CBD, presence of minor cannabinoids) modify CHS risk. Clinicians should treat the review’s recommendations as informed expert opinion rather than evidence-based guidelines. The reported association between legalization and emergency department visits is suggestive but could reflect increased recognition, improved coding practices, or changes in healthcare-seeking behavior rather than a true increase in CHS incidence.

From a pharmacological standpoint, the proposed mechanism involving chronic CB1 receptor downregulation in the enteric nervous system is plausible but unconfirmed in human tissue studies. Topical capsaicin (applied to

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