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

Medically Reviewed by Melinda Ratini, MS, DO on July 11, 2022
6 min read

Cannabinoid hyperemesis syndrome (CHS) is a rare condition that you might get if you regularly use cannabis (marijuana) for a long time. CHS causes you to have repeated episodes of vomiting, severe nausea, stomach pain, and dehydration. You have higher odds of getting it if you use marijuana at least once a week. You’re also more likely to get CHS if you’ve been using weed since you were a teenager.

CHS is not just a side effect of marijuana use. It’s a serious medical problem that can cause major health issues if you leave it untreated. It can bring on severe dehydration. If you have any symptoms of dehydration, call 911 right away. Those symptoms include:

  • Dizziness
  • Fast heartbeat
  • Rapid breathing
  • Dark urine or you don’t pee often
  • Sudden confusion
  • Fainting
  • Unexplained sleepiness or tiredness

Some heavy marijuana users may get CHS while others don’t. Experts aren’t sure exactly how weed causes CHS symptoms only in some people. Some researchers think genetics might play a role.

Marijuana has a lot of active chemical compounds called cannabinoids. When you use weed, these compounds bind to cannabinoid receptors found in your brain, digestive tract (gut), and certain cells in your body. Tetrahydrocannabinol (THC) and cannabidiol (CBD) are the main cannabinoids in marijuana products. THC is what’s responsible for the “high” most people feel when they use marijuana.

When you use marijuana for many years, it can start to slowly change how the receptors in your body respond to the cannabinoid chemicals. This may lead to CHS symptoms. For example, the drug affects the receptors in the esophageal sphincter. It’s the tight band of muscle that opens and closes to let food go from your throat to your stomach. If this flap doesn’t work properly, your stomach acids might flow upward and cause you to have nausea and vomiting.

But in the brain, marijuana usually has opposite effects of CHS. When cannabinoids bind with brain receptors, they tend to prevent nausea and vomiting.

Experts only recently discovered CHS as a medical condition. And so far, it’s known to affect only a small number of heavy marijuana users. It’s possible that many may have it but might not have gotten help or have a misdiagnosis. One study found that about 6% of people who went to an emergency room for vomiting had CHS.

Common CHS symptoms include:

  • Intense nausea
  • Several bouts of vomiting. This can happen without warning, as many as five times an hour.
  • Pain all around your stomach
  • Weight loss
  • Dehydration
  • Morning sickness
  • Fear of throwing up
  • Lack of appetite

People with CHS also tend to have a strong urge to bathe or take hot showers. That’s because it can help ease CHS symptoms like nausea. Some people may do this way too much – sometimes for many hours each day.

The symptoms are usually spread out over three phases:

Prodromal phase. This phase is most common among adults who’ve used marijuana since they were teenagers. You may have stomach pain or morning sickness. You may also have a fear of throwing up but never actually do it.

Hyperemetic phase. This phase usually lasts 24-48 hours. It can be intense and overwhelming. You may repeatedly vomit and have nausea and dehydration. You may start to bathe too much and avoid certain foods, or just not eat.

This phase may continue as long as you keep using marijuana. You’re most likely going to need medical attention during this phase.

Recovery phase. This phase starts when you stop your marijuana use. When you do this, your symptoms may start to go away over a few days or months. Over time, they’ll go away completely unless you start to use it again.

There’s no single test to diagnose CHS. If you have symptoms, your doctor will do a physical exam and ask for your detailed medical history. Let your doctor know how much marijuana you use and how often you use it. Also list any other substance use.

Your doctor may ask you questions like how long you’ve been using cannabis and what type of products you normally use. For example, if you smoke weed, eat edibles, or use tinctures, tell your doctor.

To rule out other causes of nausea and vomiting, you doctor may order tests, such as:

  • Blood tests for anemia (iron deficiency) or infection
  • Urine tests to check for infection
  • Drug tests
  • X-ray to check for blockages
  • MRI
  • Head and stomach CT scan
  • Pregnancy test
  • Test for electrolytes
  • Test for liver and pancreas enzymes
  • Endoscopy. It’s a nonsurgical procedure in which your doctor will pass a flexible tube with light and camera into your gut. This will allow your doctor to check for any internal tears or bleeds.

Because CHS is a new medical condition, not all doctors may know about it. Or they might think it’s something else. You may need to see a gastroenterologist, a doctor who specializes in the digestive tract.

There’s no specific cure, but CHS is not permanent. The only way to stop CHS symptoms is to completely stop using all marijuana products. After you quit, you may still have symptoms and side effects for a few weeks. But over time, your symptoms will go away.

During the hyperemetic phase, if you have severe vomiting for a day or more, you may need to stay in the hospital. You might need treatments like:

  • Intravenous (IV) fluids if you’re dehydrated
  • Medicines to help lessen vomiting
  • Proton-pump inhibitors. These medications treat stomach inflammation.
  • Pain medications
  • Regular hot showers to ease nausea

Symptoms usually go away in a day or two unless you use marijuana again. If you need help quitting, ask your doctor whether a drug rehabilitation program is a good fit for you.Cognitive behavioral therapy and family therapy can also help. If you’re interested, reach out to a mental health professional like a licensed psychologist or therapist.

After you quit using marijuana, CHS symptoms may continue for a few weeks. To help you transition to the recovery phase, you can try a few home remedies such as regular hot baths. But too many of them may increase your risk for dehydration due to sweating.

Your doctor may recommend certain over-the-counter medications like:

  • Antihistamines such as diphenhydramine
  • Pain relievers such as ibuprofen or acetaminophen
  • Capsaicin cream (Zostrix) to relieve pain. The chemicals in the cream have the same effect as a hot shower. In some people, it can ease nausea and vomiting when you rub it on your belly.

They may also prescribe antipsychotic medications such as haloperidol (Haldol) or olanzapine (Zyprexa) to help you calm down as you switch to the recovery phase.

If you vomit a lot, it may cause dehydration and issues with electrolytes in your blood. If you don’t get medical help soon, you might be at risk for complications that dehydration can cause, including:

  • Seizures
  • Shock
  • Kidney failure
  • Muscle spasms or weakness
  • Heart rhythm problems
  • In very rare cases, brain swelling (cerebral edema)

Besides dehydration, too much vomiting can also cause complications like:

  • Inflammation in your esophagus (esophagitis)
  • Malnutrition, or not getting proper nutrition
  • Tears in your esophagus (Mallory-Weiss syndrome)
  • Tooth decay
  • Low potassium (hypokalemia)
  • Low levels of phosphorous in the blood (hypophosphatemia)
  • Air trapped in the chest cavity between the lungs (pneumomediastium)
  • Aspiration pneumonia. This happens when you breathe vomit into your lungs or airway. This can put you at risk for choking.

The best way to prevent or reduce your risk for CHS is to avoid or quit marijuana use. It’s better to do this even if you’ve used it for several years with no symptoms or side effects.

But if you have CHS, the only option is to fully stop using it. If not, your symptoms like nausea and vomiting are likely to come back.

If you quit or cut back on marijuana, it can:

  • Improve memory and thinking skills
  • Improve lung function
  • Lead to better sleep
  • Lower your risk for depression and anxiety

If you need help quitting, ask your doctor. You can also call the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 800-662-HELP (4357). It’s a free service that’s available 24/7.