The short answer
Cannabinoid hyperemesis syndrome (CHS) is described as recurring cycles of nausea and vomiting associated with cannabis use. A systematic review of published cases and studies found regular cannabis use and cyclic nausea/vomiting among commonly reported features; hot bathing was also often reported. Much of that literature was case-based, so hot showers or cannabis history do not diagnose CHS.
Health Canada's January 2026 information guide describes CHS as repeated episodes of severe nausea, intense and prolonged vomiting, and stomach pain resistant to treatment. These symptoms can have other causes; do not delay medical assessment to test a theory.
When repeated vomiting needs help
Seek medical advice for recurring vomiting. Health Canada lists seizure, chest pain, trouble breathing, loss of consciousness and serious speech/understanding problems as medical emergencies; if a cannabis-related medical emergency occurs, call 9-1-1 and disclose cannabis use. For broader safety information, see Health Canada's older-adult overview.
Questions readers ask
Do hot showers prove CHS?
No. A systematic review found hot bathing commonly reported in case-based literature, but it is not a stand-alone diagnostic test.
Does cannabis always cause cyclic vomiting?
No. CHS is not inevitable. Recurring vomiting has multiple possible causes and needs clinical assessment.
Sources
- Health Canada: Information on the use of cannabis for medical purposes (January 2026)
- PubMed: Cannabinoid hyperemesis syndrome--systematic review
Sources checked September 24, 2026.