Cannabinoid hyperemesis syndrome (CHS) is a poorly understood clinical condition, characterized by cyclical vomiting in the context of long-term, frequent cannabis use. This condition has recently emerged as an increasing burden to emergency departments (ED) and health care systems, alongside the increased normalization of cannabis use worldwide.1 Following the commercialization of recreational cannabis in Nevada, ED visits for CHS more than doubled between 2013 and 2021, increasing from 1.07 to 2.22 per 100,000 people.2 A medical records review from Ontario, Canada found a 13-fold increase in CHS-related ED visits from pre-legalization in 2014 through legalization in 2021.3 A retrospective cohort study of electronic health records from Kaiser Permanente Northern California found that the annual prevalence of CHS increased by at least 134–175% between 2009 and 2019.4 It is unclear whether this increasing prevalence reflects the expanded U.S. cannabis legalization since 2012 or the improved recognition of CHS following its first description in 2004.5
Regardless, the increased recognition of this condition has resulted in the development of diagnostic criteria (ROME-IV) in 2016.6 Most recently, in 2025, a specific International Classification of Diseases, Tenth Revision code was established for CHS, which is expected to improve capture of the epidemiological data. Despite its increasing prevalence, the underlying pathophysiology of CHS is still not well understood, and it remains unclear why some, but not all, cannabis users develop the syndrome. Additionally, insufficiently studied factors, such as underlying genetic variation or stress regulation, may play a significant role in the pathogenesis of CHS.7–9
CHS is thought to manifest primarily, although not exclusively, in individuals with a history of frequent and long-term use of delta-9-tetrahydrocannabinol (Δ9-THC) containing products.10–12 The hallmark symptom of CHS is recurrent, severe, and refractory vomiting, frequently accompanied by abdominal pain, which is often relieved with hot bathing.13 Symptoms are typically described in three phases: prodromal, hyperemetic, and recovery.14 The prodromal phase of CHS typically precedes hyperemetic episodes. This early warning phase is an understudied component of the syndrome and is characterized by nausea, abdominal discomfort, and restlessness, during which patients often continue cannabis use with the belief that it provides relief. The hyperemetic phase involves severe, recurrent nausea and vomiting that can persist for several days, with the potential to cause life-threatening dehydration if prolonged. The recovery phase follows cannabis cessation and is marked by gradual resolution of symptoms, though relapse into the cycle is common if cannabis use resumes.15 Improved awareness and identification of prodromal symptoms could aid health care providers in recognizing CHS earlier, potentially reducing its severity and overall burden.
The existing literature lacks detailed data on cannabis use patterns among individuals with CHS, particularly in the period preceding the onset of symptoms.16 Furthermore, key information such as cannabinoid content, route of administration, dosage, and frequency of use is often absent in the literature, despite their potential relevance to diagnosis and pathology. Other factors, such as minor or synthetic cannabinoids, contaminants, pesticides, or methods of consumption, may contribute to disease progression. Specific modes of consumption may be especially important to consider, including oral ingestion, smoking flower, using vape cartridges, or dabbing concentrates (i.e., flash vaporization).17 The absence of these data leaves uncertainty regarding the role of cannabinoid use in the development of CHS.
This survey aims to build upon the existing understanding of the clinical history, symptom presentation, and cannabis use patterns associated with CHS. By elucidating these key factors, we seek to support health care professionals with the early identification of CHS symptoms through more informed history taking and to reduce harm in individuals with CHS through early intervention.8,13,14
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