Cannabis Hyperemesis Syndrome: Recognizing the Cycle of Vomiting and Relief
Cannabis hyperemesis syndrome (CHS) is a condition in which prolonged, frequent cannabis use is associated with recurring episodes of intense nausea, vomiting, and abdominal pain. During an episode, some people take repeated hot showers or baths because the heat temporarily eases their symptoms.
CHS was first described in a 2004 case series of nine people in South Australia. The original report, “Cannabinoid hyperemesis: cyclical hyperemesis in association with chronic cannabis abuse,” linked long-term cannabis use with recurrent vomiting that improved after cannabis was stopped. CHS is now recognized internationally, although its true prevalence remains uncertain and the condition may be underdiagnosed.
Who develops CHS?
CHS is most often reported in people who use cannabis heavily and regularly—typically daily or nearly daily—for months or years. Researchers have proposed several explanations, including long-term disruption of cannabinoid signaling in the brain and gastrointestinal tract, but the underlying mechanism has not been established.
The risk may be related to cumulative exposure, product potency, individual biology, and patterns of use. However, there is no reliable dose or duration that predicts exactly who will develop CHS. A person can use cannabis for years before symptoms begin.
What are the symptoms?
CHS commonly follows a repeating pattern:
- Prodromal phase: early-morning nausea, abdominal discomfort, and fear of vomiting. This phase may last for weeks or months.
- Hyperemetic phase: repeated or uncontrollable vomiting, abdominal pain, inability to keep fluids down, and frequent hot bathing or showering for relief.
- Recovery phase: symptoms improve after cannabis use stops. Resuming cannabis can cause the symptoms to return.
Hot water can provide temporary relief, but it does not treat the underlying condition or prevent dehydration. Excessive bathing also creates a risk of burns, fainting, and falls.
How is CHS diagnosed?
There is no single laboratory test that confirms CHS. Diagnosis is based on the patient’s history, symptom pattern, cannabis exposure, and improvement after sustained cessation. Clinicians must also consider and rule out other causes of vomiting, including infection, medication effects, pregnancy-related illness, bowel obstruction, pancreatitis, gallbladder disease, cyclic vomiting syndrome, and other urgent conditions.
Patients should tell their healthcare provider how often they use cannabis, which products they use, and when their symptoms began. Blood and urine tests may be used to assess dehydration, kidney function, and electrolyte abnormalities or to investigate alternative diagnoses. The American Gastroenterological Association’s clinical practice update on CHS provides additional guidance for clinicians.
How is it treated?
The only established long-term treatment is complete cessation of cannabis. Stopping temporarily, switching products, or choosing a lower-THC product has not been shown to reliably prevent another episode. People who have difficulty stopping may benefit from support for cannabis use disorder, including counseling and treatment from a healthcare professional.
During an acute episode, medical treatment may include intravenous fluids, correction of electrolyte abnormalities, and medicines for nausea and vomiting. Clinicians may consider treatments such as haloperidol or topical capsaicin in appropriate patients, but these should be used under medical supervision. The NCBI clinical overview of cannabinoid hyperemesis syndrome summarizes current diagnostic and treatment considerations.
Anyone who cannot keep fluids down, is urinating very little, feels faint or confused, has severe or worsening abdominal pain, vomits blood, or develops chest pain or trouble breathing should seek urgent medical care. Repeated vomiting can cause dehydration, dangerous electrolyte and metabolic disturbances, acute kidney injury, malnutrition, aspiration, and injuries to the esophagus. Death is rare but has been reported in association with severe complications.
Cannabis use during pregnancy or breastfeeding
Pregnancy-related vomiting can resemble CHS, and cannabis use can make it harder to determine the cause. Pregnant or breastfeeding people should discuss cannabis use with a healthcare professional rather than trying to manage persistent vomiting on their own. The Centers for Disease Control and Prevention’s guidance on cannabis and pregnancy recommends avoiding cannabis during pregnancy and breastfeeding because cannabis chemicals can reach the fetus or infant and the health effects are not fully understood.
CHS is serious but treatable. Recognizing the connection between recurrent vomiting and frequent cannabis use can help patients avoid repeated hospital visits and prevent complications. For people with CHS, sustained avoidance of cannabis is the key to recovery and the best way to reduce the risk of recurrence.
