cannabis hyperemesis syndrome (CHS)

Cannabis hyperemesis syndrome (CHS) is a disorder of gut-brain interaction with symptoms of nausea, severe episodic vomiting, and abdominal pain (1,2,3):

• Marijuana, the most common cannabis product, is a mixture of dried flowers, leaves, and seeds from cannabis plants
  • the primary psychoactive ingredient in cannabis is Δ⁹ tetrahydrocannabinol (THC)
• CHS describes a collection of symptoms that include severe episodic vomiting and abdominal pain in patients who use cannabis frequently (usually daily) for a prolonged time (usually a year or more)
  • CHS is characterized by (3):
    • 1) several years of preceding cannabis use, predating the onset of illness;
    • 2) a cyclical pattern of hyperemesis every few weeks to months, at which time the patient is still using cannabis
    • 3) resolution of the symptoms after cessation of cannabis use, confirmed by a negative urine drug screen.
• primary pathways implicated in CHS are the endocannabinoid system and the transient receptor potential vanilloid-1 pathway
  • lack of cannabis standardization and Fusarium mycotoxin contamination may also play a role in the development of CHS (1)
• CHS appears to be due to chronic overstimulation of endocannabinoid receptors, leading to derangements in the body’s intrinsic control of nausea and vomiting (3)
  • while the sensation of nausea is primarily a neurologic phenomenon, CHS is largely classified as a chronic disorder of gut-brain interaction, not primarily a neurologic disorder (1)
    • nausea is mediated by the area postrema and central emetic pathways
    • a key component of these pathways is the endocannabinoid system (ECS), which consists of a retrograde signaling pathway activated by CB1 in the CNS and gut
    • the ECS is a neuromodulator and regulator of nausea and vomiting, particularly during stress response
    • chronic use of cannabis down-regulates and de-sensitizes CB1 receptors
      • leads to a decrease in ECS signaling that is inversely correlated to the activation of the hypothalamic-pituitary stress axis (HPA)
      • the increased activation of the HPA may account for the vomiting effect of anxiety, which is also observed in many patients with CHS
  • note that the transient receptor potential vanilloid-1 (TRPV1) nociceptor is also influenced by cannabinoids
• hot showers, capsaicin, and antipsychotics – but not traditional anti-emetics – have been shown effective for symptom management:
  • the almost pathognomic aspect of a patient's presenting history is that their symptoms are relieved by hot baths or showers (3)

Management (1,2,3):

• seek expert advice
• fluid resuscitation
  • aggressive IV fluid rehydration and correction of electrolyte imbalances (e.g., hypokalaemia, hyponatraemia) caused by severe emesis
• anti-emetics are relatively ineffective at treating CHS
  • standard antiemetics (ondansetron, metoclopramide) and opioids are often ineffective in CHS
• antipsychotics in CHS
  • in case series and small clinical trials, anti-psychotics have been shown more effective in treating nausea, abdominal pain, and vomiting linked to CHS (1)
  • haloperidol or droperidol (IV/IM)
    • highly effective in ED settings for rapid relief of nausea and severe abdominal distress
• capsaicin in CHS
  • the TRPV1 channel binds to capsaicin, a chemical found in chili peppers, which controls the release of substance P (a mediator involved in pain perception)
  • capsaicin is a TRPV1 agonist
    • has an anti-emetic effect in CHS
    • acts as a TRPV1 agonist to reduce substance P release and alleviate nausea/pain similarly to hot water exposure
• cannabis cessation is the only definitive intervention for full resolution of hyperemetic episodes
  • symptoms typically improve within days to weeks, though tissue clearance of lipophilic cannabinoids can take several weeks to 45+ days in chronic heavy users (4)

Reference:

1. Romero PJ et al. Cannabis hyperemesis syndrome: Pharmacological and toxicological perspectives. Current Opinion in Toxicology March 2026.
2. Venkatesan T, Hasler WL, Camilleri M. Cannabinoid Hyperemesis Syndrome. JAMA. Published online August 26, 2026.
3. Cue L, Chu F, Cascella M. Cannabinoid Hyperemesis Syndrome. [Updated 2023 Jul 3]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-.
4. Siragusa N et al. The Near-Fatal Bath: A Case Report With Literature Review of Diagnosis and Management of Cannabinoid Hyperemesis Syndrome, Case Reports in Medicine, 2026.