Cannabinoid Hyperemesis Syndrome (CHS): Symptoms, Causes and Treatment

Cannabinoid hyperemesis syndrome, or CHS, is one of the stranger paradoxes in medicine: a drug widely used to prevent nausea can, in long-term frequent users, cause some of the most severe vomiting emergency departments see.

People with CHS cycle through episodes of relentless nausea, vomiting and abdominal pain, often finding relief only in scalding hot showers. Because cannabis has a reputation as an anti-nausea remedy, many people respond to the vomiting by using more — which keeps the cycle going. CHS is frequently misdiagnosed for months or years, and the only treatment that reliably ends it is stopping cannabis use.

What Is CHS?

CHS is a condition that develops in some people who use cannabis frequently — typically daily or near-daily — over a period of years. It causes recurring bouts of severe nausea, repeated vomiting and crampy abdominal pain, separated by stretches of feeling relatively normal.

The exact mechanism is not fully understood. The leading explanation is that chronic THC exposure dysregulates the cannabinoid receptors involved in nausea signaling and in the body's stress and temperature regulation systems. What began as an anti-nausea effect flips, and the gut-brain signaling that normally suppresses vomiting instead drives it.

CHS is not the same as greening out. A green-out is a one-time reaction to too much THC in a single sitting. CHS is a chronic condition tied to cumulative, long-term use, and it can strike even when the person has not consumed more than usual.

The Three Phases of CHS

CHS typically moves through recognizable phases.

Prodromal phase

Early-morning nausea, anxiety about vomiting and vague abdominal discomfort, often lasting months or years. Appetite and eating usually remain normal. Many people increase their cannabis use during this phase, believing it will settle their stomach.

Hyperemetic phase

The acute crisis. Intense, unrelenting vomiting — sometimes dozens of episodes in a day — with nausea, abdominal pain, sweating and food aversion. The informal term "scromiting" (screaming plus vomiting) originated in emergency departments describing patients in this phase. Dehydration and electrolyte imbalances are the main medical dangers, and severe cases can lead to kidney injury.

This is also the phase marked by compulsive hot bathing. Many people with CHS discover that very hot showers or baths temporarily quiet the nausea — a clue so characteristic that clinicians use it to help identify the condition. The relief is thought to relate to the way cannabinoid signaling interacts with the body's temperature regulation.

Recovery phase

When cannabis use stops, symptoms fade — sometimes within days, more often over weeks to months as THC stored in body fat clears. Appetite, weight and normal bathing habits return. If cannabis use resumes, the syndrome almost always returns with it.

Signs You May Be Dealing with CHS Rather Than a Stomach Problem

CHS is routinely mistaken for food poisoning, gastritis, cyclic vomiting syndrome or gallbladder disease. Consider CHS when several of these are true:

• Cannabis use has been frequent (daily or near-daily) for a year or more
• Vomiting comes in repeated episodes with symptom-free periods between them
• Hot showers or baths bring temporary relief
• Standard anti-nausea medications help little
• Symptoms improve during breaks from cannabis and return with resumed use

A medical evaluation is still essential. Severe recurrent vomiting has many possible causes, and a clinician needs to rule out conditions that require different treatment. Be honest about cannabis use during that evaluation — clinicians cannot diagnose CHS if they do not know about the exposure, and the condition is missed for exactly that reason all the time.

How CHS Is Treated

During an acute episode

Emergency treatment focuses on stopping the vomiting and repairing its effects: IV fluids for dehydration, electrolyte replacement and antiemetic medications. Some medications not typically used for nausea — including certain antipsychotics and topical capsaicin cream applied to the abdomen — have shown benefit for CHS specifically. Hot showers remain a temporary comfort measure, not a treatment.

Ending the syndrome

The only intervention that reliably resolves CHS is stopping cannabis use completely. Cutting back rarely works, and switching products does not help, because the syndrome is driven by THC exposure itself. Symptoms may take weeks to fully resolve after quitting, which leads some people to conclude prematurely that quitting "didn't work" and resume use.

Support for quitting

For a daily, long-term user, stopping cannabis is harder than it sounds — particularly when cannabis has also been serving as a tool for managing anxiety, sleep or mood. Cannabis withdrawal (irritability, insomnia, restlessness, low appetite) is real, and the underlying reasons for heavy use do not disappear when the vomiting does. Behavioral health treatment, whether outpatient or residential, can address both the cannabis use disorder and any co-occurring anxiety, depression or trauma driving it. That combination is what makes quitting stick.

When to Seek Emergency Care

Go to an emergency department for:

• Vomiting that will not stop or lasts more than 24 hours
• Signs of severe dehydration — minimal urination, dizziness on standing, confusion
• Blood in vomit
• Severe abdominal pain
• Inability to keep any fluids down

Call Poison Control at 1-800-222-1222 for guidance if the situation is concerning but does not appear immediately life-threatening.

At a Glance

CHS causes cycles of severe vomiting and abdominal pain in long-term frequent cannabis users, often with the telltale sign of relief from hot showers. It is commonly mistaken for other stomach conditions, and using more cannabis to treat the nausea keeps the cycle going.

Acute episodes are managed with fluids and medication, but the only reliable cure is stopping cannabis entirely — and staying stopped. Recovery can take weeks. For daily users, structured support for quitting, including treatment for the anxiety or mood symptoms that drove heavy use, gives the best odds of lasting resolution.

Sources

• Cannabinoid Hyperemesis Syndrome — StatPearls, NCBI Bookshelf
• Cleveland Clinic: Cannabinoid Hyperemesis Syndrome (CHS)
• Cannabis hyperemesis syndrome: an update on the pathophysiology and management — PMC
• National Institute on Drug Abuse: Cannabis

Prefer another language? Read about cannabinoid hyperemesis syndrome in Spanish: síndrome de hiperemesis cannabinoide, or in Hindi: कैनाबिनॉयड हाइपरमेसिस सिंड्रोम.