ClearCHS Foundation
What Is Cannabinoid
Hyperemesis Syndrome?
CHS is a recognized medical condition caused by long-term, heavy cannabis use — far more common than most people, including many doctors, realize. If you've been searching for answers, you're in the right place.
Americans estimated to be affected by CHS every year
Emergency department visits for CHS doubled between 2017 and 2021 in the US and Canada
Average time many patients spend misdiagnosed before receiving correct answers
It's a Real Condition — Not a Fluke
CHS triggers repeated cycles of severe nausea, vomiting, and intense abdominal pain. It is not a sensitivity, an allergy, or a character flaw. It is a physiological reaction — and it's increasingly common as cannabis has become more potent and more widely legal.
As cannabis use has expanded — and as THC concentrations in cannabis products have risen dramatically since the 1990s — CHS has become more widespread. Today's cannabis is substantially more potent than it was a generation ago, and the body bears the consequences.
Despite its prevalence, CHS remains widely misdiagnosed — often for years — because many clinicians simply aren't familiar with it yet. That's something the ClearCHS Foundation is working to change.
Why Does Cannabis Cause This?
It seems like a contradiction — cannabis is commonly used to treat nausea, including in chemotherapy patients. So how can it also cause it?
The answer lies in long-term, heavy use. Over time, chronic overstimulation of cannabinoid receptors — particularly in the gut — can disrupt the body's natural regulation of nausea and vomiting.
The brain and digestive system stop responding to cannabis the way they once did. What started as relief can quietly become the cause.
Who Gets CHS?
CHS most commonly affects people who use cannabis daily or near-daily for more than a year — and often doesn't appear until after a decade or more of regular use. It tends to affect males more than females, and is most prevalent among people aged 16 to 34, though it can affect anyone.
Risk factors include using cannabis before age 16, as well as concurrent use of tobacco or other substances.
Risk Factors at a Glance
- 1 Daily or near-daily cannabis use for more than a year — often more than a decade before CHS appears
- 2 Age 16–34 is the highest-prevalence range, though CHS is not limited to this group
- 3 Starting cannabis use before age 16 significantly increases risk
- 4 Concurrent tobacco or substance use is associated with elevated risk
- 5 Male sex is more commonly affected, though the gap is narrowing as use patterns change
The Three Phases of CHS
CHS typically unfolds in a predictable pattern. Recognizing where you are in this progression is an important first step toward understanding what's happening.
Prodromal Phase
Early morning nausea, mild abdominal discomfort, and sometimes a fear of vomiting. Many people increase their cannabis use during this phase, believing it will help.
Hyperemetic Phase
Overwhelming, repeated vomiting — sometimes up to five times per hour — along with severe abdominal cramping and inability to eat. This is the phase that typically drives people to the ER.
Recovery Phase
Symptoms resolve after cannabis use stops completely. Significant improvement typically begins within a few days to two weeks. Full recovery can take months.
How Is CHS Diagnosed?
There is no single lab test or scan that confirms CHS. Diagnosis is based on clinical history — which is a large part of why it takes so long for so many people to get answers.
Standard Diagnostic Criteria
- Long-term, frequent cannabis use
- Recurring episodes of severe cyclic vomiting
- Abdominal pain
- Symptom relief with cannabis cessation
- Hallmark temporary relief from hot water (shower or bath)
Frequently misdiagnosed as: Cyclic Vomiting Syndrome (CVS), gastroparesis, or other gastrointestinal conditions. If you've been through extensive testing with no clear answers and you use cannabis regularly, CHS deserves serious consideration.
Treatment
The only permanent cure for CHS is complete cessation of cannabis use. There is currently no FDA-approved medication specifically for CHS, but acute symptoms can be managed.
Acute / ER Management
- IV fluids to address dehydration
- Topical capsaicin cream applied to the abdomen
- Haloperidol or benzodiazepines for severe nausea (in some cases)
- Standard anti-nausea medications like ondansetron often do not work well for CHS — worth knowing before your next ER visit
Long-Term Recovery
- Complete cannabis cessation
- Counseling and cognitive behavioral therapy (CBT)
- Tricyclic antidepressants (e.g., amitriptyline) during the transition
Quitting cannabis is hard. Cannabis use disorder is real, and relapse rates are high. You don't have to do this alone — support matters.
Trusted Medical Resources
These sources were used to build this site and are recommended for further reading by patients, families, and clinicians.
Cleveland Clinic
A patient-friendly overview covering symptoms, phases, diagnosis, and treatment of Cannabinoid Hyperemesis Syndrome.
CHS Overview →NIH / StatPearls
A detailed clinical reference covering pathophysiology, diagnosis criteria, and treatment options — written for providers but accessible to informed patients.
NIH StatPearls →JAMA Patient Page (2024)
A concise, peer-reviewed patient summary published in the Journal of the American Medical Association.
JAMA CHS Page →American College of Gastroenterology
The leading professional gastroenterology organization — a useful resource for finding a specialist who understands CHS.
gi.org →SAMHSA National Helpline
Free, confidential, 24/7 treatment referral and support for substance use disorders. In English and en Español.
Not sure where to start?
Take the CHS Assessment to review your symptoms against established clinical criteria.
Take the AssessmentYou Deserve Real Answers
CHS is real, it is treatable, and you are not alone. The ClearCHS Foundation exists to make sure no one spends years searching for information that should be easy to find.
