What Is CHS (Cannabinoid Hyperemesis Syndrome) and Who Is at Risk?

Scromiting. That’s the nickname that stuck when emergency room doctors started running into something strange. Heavy daily cannabis users, most of them in their 20s and 30s, showing up vomiting uncontrollably and screaming from stomach pain. The one thing that brought temporary relief was a scalding hot shower. The only thing that actually cured it was quitting weed.

Welcome to cannabinoid hyperemesis syndrome. It’s real, it’s climbing fast, and the mechanism behind it is genuinely weird. If you smoke heavy and daily, you should know what this looks like.

What Is Cannabinoid Hyperemesis Syndrome?

CHS is a condition where long-term, frequent cannabis use causes cycles of severe nausea, vomiting, and abdominal pain. The paradox hits right away. THC is used medically to prevent nausea, including during chemotherapy. In CHS, cannabis does the opposite. Heavy repeated exposure flips the switch, and the same plant that stops one person’s chemo nausea puts another person in the ER.

The syndrome was first described by Australian doctors in 2004 after a cluster of chronic cannabis users showed up with unexplained cyclical vomiting. One woman in that original study reported she’d burned herself three times in hot baths trying to get relief. That compulsive hot-water bathing became one of the defining diagnostic markers, and the condition has been on the radar ever since.

What Are the Symptoms of CHS?

CHS moves through three phases. Recognizing them matters because the middle phase is what lands people in hospital beds.

Prodromal phase. Early morning nausea, mild stomach discomfort, and anxiety about throwing up. No actual vomiting yet. This stage can last months or even years. People often lean harder on cannabis to treat the nausea, which makes things worse.

Hyperemetic phase. The full syndrome. Violent, uncontrollable vomiting. Retching up to five times per hour. Severe stomach pain. Episodes typically last 24 to 48 hours and can repeat every few weeks or months. Dehydration is the main medical risk. Many people discover that very long, very hot showers provide temporary relief, which leads to compulsive bathing that can go on for hours.

Recovery phase. Once cannabis use stops, symptoms gradually fade. Full recovery usually takes about two weeks, though some people continue to have nausea or cyclic vomiting for up to 90 days while THC clears from fat stores. Pick up again, symptoms come back.

Why Does CHS Happen?

Your body has an endocannabinoid system with receptors throughout the brain, gut, and nervous system. Cannabis binds to those receptors. At normal doses, the brain’s response dominates, which is why you get the standard anti-nausea, appetite-increasing, euphoric effects.

Repeated heavy exposure appears to change how those receptors respond, particularly in the gut. The current working theory is that the digestive system’s response eventually overrides the brain’s response, flipping cannabis from anti-emetic to emetic. The thermoregulatory piece, which involves the hypothalamus, is thought to explain the strange hot-shower relief.

Honest answer: science still doesn’t fully understand it. Genetics, early age of first use, and psychological stress all look like contributing factors. Nobody has cracked exactly why some heavy users develop CHS and others never do.

Who Is at Risk for CHS?

This is the part worth getting specific about, because CHS is not a random lightning strike. It has a profile.

Daily or near-daily users. A George Washington University study of people with CHS found that over 40% used cannabis more than five times per day before symptoms began, and most were using daily.

Long-term users. The same George Washington data showed 44% of CHS sufferers had been using regularly for more than five years before symptoms started. Traditional medical guidance pointed to 10-plus years of daily use, but shorter timelines are becoming more common as potency climbs.

Heavy consumers of high-THC products. The rise of 80%-plus THC concentrates, dabs, and premium flower has clearly shifted the risk profile. Researchers now link high-potency cannabis directly to the increase in CHS cases.

Young adults, mostly. Most studies show the highest rates in adults aged 18 to 35, the group most likely to use cannabis heavily and daily. Cases are also increasingly reported in adolescents who started young.

Early-onset users. People who started consuming cannabis in their teens are showing up with CHS symptoms earlier and in higher proportions than people who started later.

Genetics likely plays a role too, but there’s no test for susceptibility. You only find out you’re vulnerable by developing it.

Why Are CHS Cases Rising?

CHS has gone from medical curiosity to public health concern in roughly a decade. Several things are driving that.

Legalization has expanded access. More than 20 states plus DC now allow recreational cannabis. Daily use has climbed alongside that. Products have gotten much stronger. Modern concentrates and flower are nothing like what was circulating in the 1990s. Dispensaries routinely sell concentrates testing above 80% THC.

The numbers back the trend. ER visits for CHS roughly doubled in the US and Canada between 2017 and 2021, and one extrapolation estimated up to 2.75 million Americans may experience CHS symptoms each year. Virginia alone reported a 29% rise in CHS-related emergency department visits between 2020 and 2024. Similar spikes have been documented in Colorado, Massachusetts, and Northern California.

In late 2025, the World Health Organization officially added CHS to its diagnostic manual, giving the condition its own international diagnostic code. That means better tracking going forward and less misdiagnosis in ERs where it’s often confused with cyclic vomiting syndrome, food poisoning, or gastritis.

How Is CHS Treated?

Hospitals can manage the acute episode. IV fluids for dehydration. Anti-nausea medication, with haloperidol showing better results than ondansetron in recent trials. Topical capsaicin cream on the abdomen sometimes helps. Hot showers continue to provide temporary relief during flare-ups.

None of that cures it. The only known cure is stopping cannabis use completely. Cutting back doesn’t work. Switching strains doesn’t work. Waiting it out while still consuming doesn’t work. Full abstinence is the treatment, and symptoms usually resolve within two weeks, though lingering nausea can stretch up to 90 days.

If you relapse, symptoms come back almost every time. That’s the pattern in nearly every documented case.

A Breeder’s Take on the Potency Problem

We’ve been breeding cannabis for over three decades. What we see in today’s market is a plant pushed into territory the old heads never imagined. THC percentages that were once extraordinary are now baseline expectations. Concentrates isolate the psychoactive punch and strip away the balance that whole flower naturally provides.

The cannabis plant didn’t evolve to deliver 90% THC. It produces dozens of active cannabinoids and hundreds of terpenes that modulate each other in ways pharmacology is still catching up on. When you blow out the THC curve and remove the supporting cast, you’re asking your endocannabinoid system to process something the plant doesn’t actually make on its own.

Our genetics work focuses on balance. High-THC strains have a place in the catalog because that’s what a lot of growers want, and we push those numbers as hard as anyone. But the real craft sits in the terpene profile, the cannabinoid ratio, the shape of the high rather than just the ceiling. Strains we’ve kept in rotation for years, like Acapulco Gold and LSD, earn their spot because the terpene expression carries the experience, not a max-THC number. A well-bred flower at 18% with a rich aromatic profile is a different beast from an 85% extract, and the body knows the difference.

CHS doesn’t hit every daily user. But the risk curve clearly bends toward heavy, constant, high-potency consumption. From the breeding side, our view is that variety, moderation, and respect for the plant’s complexity are part of what keeps cannabis working long-term for the people who love it. Rotating strains, taking tolerance breaks, and leaning into full-spectrum flower over concentrate-only routines aren’t old-school habits for nothing.

What to Do If You Think You Have CHS

If you’ve been a heavy, regular consumer for years and you’re dealing with cycles of severe vomiting, intense stomach pain, and an unexplained dependence on long hot showers, talk to a doctor and be honest about your cannabis use. CHS gets misdiagnosed as cyclic vomiting syndrome or gastritis when patients stay quiet about what they’re consuming. The treatment only works if the diagnosis is right, and the diagnosis only lands if your doctor knows what you’re actually using and how often.

Cannabis will be there if you come back to it. A ruptured esophagus, kidney failure from dehydration, or a permanent fear of eating will be harder to undo.

Barney's Farm has been developing premium cannabis genetics since the 1980s, with over 40 Cannabis Cup wins. Explore our full cannabis seed catalog and find strains bred for every climate and skill level.