In recent years, hospitals across the United States have seen a concerning surge in a peculiar but serious condition: repeated bouts of intractable nausea and vomiting associated with long-term cannabis use. The cause? A little-known, often misdiagnosed disorder called Cannabinoid Hyperemesis Syndrome (CHS).

CHS can start quietly. For many users, it begins years after they first started using cannabis regularly—daily or near-daily, often for stress relief, pain management, or recreational use. They’re not expecting danger. For most, cannabis carries a reputation as among the “safer” substances. Yet for a subset of chronic users, the risk is real, and growing.

What Is CHS — And Why It’s So Dangerous

According to a detailed overview by Cleveland Clinic, CHS is characterized by cycles of nausea, abdominal pain, and recurrent vomiting.  These symptoms often emerge after many years of frequent cannabis use. In clinical settings, the vomiting can be severe — described by some patients as happening “up to five times an hour,” accompanied by excruciating abdominal pain and dehydration.

One of the striking hallmarks of CHS is a strong, often compulsive urge to take hot showers or baths during episodes. For many sufferers, the hot water offers temporary relief — sometimes the only relief.

Medical professionals divide CHS into three clinical phases:

• Prodromal phase: early morning nausea, vague discomfort, fear of vomiting — sometimes without actual vomiting. This phase may last for months or years.
• Hyperemetic phase: intense, repeated vomiting, severe nausea, abdominal pain, dehydration — often requiring emergency care.
• Recovery phase: symptoms decrease gradually if cannabis use is stopped entirely.

Right now, the only consistently effective treatment is complete cessation of cannabis use. Anti-nausea drugs and IV fluids may ease dehydration and discomfort, but they do not reliably stop CHS itself.

Why Are Doctors Seeing More CHS Cases?

Multiple recent studies suggest that CHS is no longer rare — it’s becoming a common cause of repeated vomiting visits to emergency departments (EDs), especially among young adults.

A landmark 2025 study published in JAMA Network Open analyzed nearly 189 million Emergency Department visits in the U.S. between 2016 and 2022. It found that suspected CHS increased from 4.4 per 100,000 visits in 2016 to 22.3 per 100,000 in 2022, with a peak of 33.1 per 100,000 in the second quarter of 2020.

The increase during the COVID-19 pandemic (2020–2021) was especially steep, suggesting that changes in lifestyle, increased cannabis use, and stress may have contributed.

CHS cases have clustered heavily among individuals aged 18 to 35 years — the age group most likely to use cannabis heavily and frequently.

Another worrying trend: in a 2023 study among adolescents (age 13–21), ED visits for CHS rose dramatically — showing a nearly 50% increase per year between 2016 and 2023.

Together, the data suggest that as cannabis use becomes more widespread — aided by legalization, higher potency products, and social acceptance — CHS is emerging as a real public health concern.

Why It’s So Hard to Recognize — And Often Mistaken

One reason CHS went under the radar for so long is how easily it can be mistaken for other conditions. Early symptoms mimic common ailments: morning nausea might be dismissed as stress, food poisoning, or acid reflux. A bout of vomiting might seem like the flu. Hot showers seem like a curious self-soothing behavior — but not a symptom worth reporting.

Even among medical professionals, awareness has lagged. CHS was underdiagnosed or misdiagnosed for years. Often patients underwent repeated rounds of tests, imaging, fluids, and anti-emetics — only to have symptoms return again and again.

The situation is improving. In recent years, more hospitals and ERs have adopted standard diagnostic criteria using ICD-10 codes (e.g., F12.x combined with vomiting codes) to flag suspected CHS cases when patients present with chronic vomiting plus a history of cannabis use.

Still, the lack of a reliable biological test, and the fact that cannabis isn’t always voluntarily disclosed by patients, means many cases likely remain unrecognized.

What Researchers Think Causes CHS — And What We Don’t Know

While the exact mechanism behind CHS is not fully understood, the leading theory centers on long-term overstimulation of the body’s endocannabinoid system. This system — which regulates nausea, digestion, pain, mood, and many other functions — becomes disrupted with persistent high-dose cannabis exposure. Over time, the receptors may begin to malfunction, reversing cannabis’s typical anti-nausea effects and triggering cyclic vomiting.

Additional factors that may increase risk of CHS:

• Frequent or daily cannabis use, especially over many years.
• High-THC potency products — modern concentrates, edibles, or strong strains may put heavier stress on the system than older, less powerful varieties. This aligns with increased CHS case numbers following legalization and rising potency.
• Age at first use — some evidence suggests that individuals who begin cannabis use in adolescence or young adulthood may have higher risk of developing CHS later.
• Individual vulnerability — genetics, metabolic factors, and personal biology may determine who’s susceptible and who isn’t. Not all heavy users develop CHS.

At this point, scientists do not yet know why CHS affects some users and not others — a variation in “threshold” seems likely. That ambiguity complicates prevention and early diagnosis efforts.

Why Quitting Cannabis is the Only Real “Cure”

Because the root problem appears to be chronic overstimulation of the endocannabinoid system, the only consistent way to stop CHS is to stop using cannabis entirely.

During an episode, medical care might provide short-term relief: IV fluids, rehydration, supportive care, sometimes medications. Hot showers or capsaicin cream on the abdomen can ease the nausea temporarily.

But as long as cannabis use continues, the cycle returns. For many sufferers, quitting isn’t easy — especially if they rely on cannabis for chronic pain relief, anxiety, insomnia, or recreational use.

That’s why health experts emphasize awareness: if someone has repeated episodes of vomiting, severe nausea, abdominal pain — especially if they are a regular cannabis user — they should discuss CHS with a health provider. Early recognition can prevent repeated hospitalizations, dehydration, electrolyte problems, and severe weight loss.

What the Surge in CHS Cases Tells Us About Changing Cannabis Use in America

The rise of CHS isn’t happening in a vacuum. It reflects broader shifts in cannabis consumption over the last decade: growing legalization, increasing social acceptance, development of stronger products, and more frequent use by younger adults.

• The 2025 JAMA-Network Open study shows CHS diagnoses soared between 2016–2022, especially among 18–35 year olds.
• Adolescent CHS-related ER visits have also climbed significantly from 2016 to 2023.
• Increased access to high-potency cannabis via dispensaries and products like concentrates, vapes, and edibles may play a substantial role.

As a result, CHS is emerging as a public health challenge, especially in regions where cannabis is legal, availability is high, and young adults consume regularly.

What We — And Health Professionals — Should Do Now

Given the growing evidence, a few clear steps emerge:

1. Raise awareness — both among users and medical professionals. Many people still view cannabis as harmless. But chronic high-frequency use carries risks that aren’t widely understood.
2. Standardize diagnosis — widespread use of ICD-10 codes, better screening for cannabis use in patients with recurrent vomiting or nausea.
3. Educate on safer use or abstinence — individuals using cannabis for therapy or recreation should understand that “smoke frequently over years” may carry long-term risks.
4. Support cessation programs — for chronic users, quitting can be difficult. Medical guidance, counseling, and support are needed to help them stop safely.
5. Further research — scientists must continue to study why CHS affects some but not others, how potency and frequency influence risk, and whether there are other safe treatments or preventive strategies.

Final Thoughts: CHS Is Real — And It’s Growing

Cannabis has long been considered among the “safer” psychoactive substances. But as use becomes more widespread — and products become stronger — so do the risks. CHS is a stark example: what once was rare now shows up repeatedly in emergency rooms across the country, especially among younger adults with chronic use.

For those experiencing repeated vomiting, intense nausea, and abdominal pain — especially if they take long hot showers to find relief — CHS should be on the radar.

Quitting cannabis isn’t easy. But for many, it may be the only real way to end the cycle of suffering.

If nothing else, CHS reminds us that even substances seen as benign can carry hidden dangers when used heavily long-term. Awareness, honesty, and medical care can make all the difference.