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

Medically Reviewed by Jabeen Begum, MD on June 13, 2024
Written by Shishira Sreenivas, Kathryn Whitbourne
8 min read

Cannabinoid hyperemesis syndrome (CHS) is a condition that you might get if you've regularly smoked weed or used marijuana in some other form for a long time. CHS causes you to have repeated episodes of vomiting, severe nausea, stomach pain, and dehydration. You're more likely to get CHS if you use marijuana at least once a week and have been doing so since you were a teenager. "Cannabinoid" refers to cannabis (marijuana) and "hyperemesis" is a word meaning "prolonged vomiting."

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 severe dehydration, like dizziness, confusion and a rapid heartbeat, call 911 right away. 

How rare is CHS?

CHS was first described as a medical condition in 2004. Although it was considered to be rare, the number of cases has increased with the legalization of marijuana in many places and the opening of retail stores to easily get it. This has increased both the number of people using the drug and the "high" in the available weed. 

One 2018 study found that 32.9% of self-reported frequent marijuana users who'd gone to the emergency room (ER) had symptoms of CHS. And a 2022 Canadian study found that ER visits for CHS-related problems had increased 13-fold between 2014 and 2021. (Recreational use and sale of cannabis in Canada was legalized starting in 2018). It's not clear what percentage of all heavy marijuana users have experienced CHS.

Some people who use marijuana heavily get CHS while others don’t. Researchers aren’t sure exactly why weed causes CHS symptoms only in some people. They 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, 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.

While marijuana seems to bring on nausea in the stomach, in the brain it usually has opposite effect. When cannabinoids bind with brain receptors, they tend to prevent nausea and vomiting. Experts think that when you first smoke weed, your brain signals are more important, but after repeated use of the drug, the brain receptors may no longer respond to marijuana in the same way, causing more nausea and vomiting.

 

Common CHS symptoms include:

  • Intense nausea
  • Several bouts of vomiting. This can happen without warning, as many as 5 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 take very hot showers or baths. That’s because hot water can help ease cannabinoid hyperemesis syndrome symptoms like nausea. The hot temperature affects a part of the brain called the hypothalamus, which regulates temperature and throwing up. Some people end up showering for several hours each day.

Scromiting

This word is a combination of "screaming" and "vomiting." You're in so much pain that you're screaming while you're vomiting. 

CHS without vomiting

In the first phase of CHS (the prodromal phase), you don't vomit. You think you might, but it doesn't happen. To be diagnosed with CHS, some throwing up must take place.

The symptoms of cannabinoid hyperemesis syndrome are usually spread out over three phases:

Prodromal phase

The CHS prodromal phase is most common if you’ve used marijuana since you were a teen. You may have:

  • Stomach pain or morning sickness
  • A fear of throwing up but never actually do it
  • Normal eating patterns and use more weed to keep the nausea at bay

Hyperemetic phase

This usually lasts 24-48 hours. It can be intense and overwhelming. You may:

  • Repeatedly throw up 
  • Have nausea and dehydration
  • Start to bathe/shower too much
  • Avoid certain foods, or just not eat

This phase could continue as long as you keep using marijuana. You’re most likely going to seek medical care during this phase.

Recovery phase

The CHS recovery phase starts when you stop your marijuana use. When you do this, your symptoms usually start to go away in few days to a few months. The vomiting should stop in a day or two. Over time, the symptoms will go away completely unless you start to use 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, use tinctures, or dab or vape THC, tell your doctor about any or all of them.

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 fairly new medical condition, not all doctors know about it. Or they might think it’s something else, since repeated throwing up is a sign of many health problems. You may need to see a gastroenterologist, a doctor who specializes in the digestive tract, for a proper diagnosis.

 

 

There’s no specific cure for CHS, but it's not permanent. The only way to end CHS symptoms is to completely stop using all marijuana products. After you quit, you may still have symptoms and side effects for a few days to 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

As long as you don't use marijuana, your symptoms shouldn't return. 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.

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 (Benadryl)
  • Pain relievers such as acetaminophen (Tylenol) or ibuprofen (Aleve, Motrin)
  • 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.

Cannabinoid hyperemesis syndrome trigger foods

One study looking at Reddit posts on the subject found that spicy food, greasy food, coffee, black tea, and alcohol were frequently mentioned as CHS triggers. These foods/beverages are mostly acidic, but relationships between them and CHS have not been studied scientifically, although the co-use of weed and alcohol is well-known, the study authors said. 

If you vomit a lot, CHS may cause dehydration and issues with electrolytes in your blood. Electrolytes are essential minerals in your body that have a positive or negative charge. 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 and only way to prevent or reduce your risk for CHS is to avoid or quit marijuana use. 

If you have CHS and don't stop using, 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.

Call 911 or go to the ER if you have the following signs of dehydration:

  • Dark yellow pee or very little of it
  • Dizziness
  • Feelings of confusion
  • Fatigue
  • Fast heart rate
  • Rapid breathing 
  • Fainting

If you have cannabinoid hyperemesis syndrome (CHS), the best treatment is to stop using weed, even if you've been doing it for years with no previous side effects. Once you do that, your repeated nausea and vomiting should go away and not return. Since THC is stored in your body fat, it can take weeks to months before all the symptoms go away and you notice a difference. Give it time. Smoking extra marijuana won't help your nausea but will make it worse.

Over-the-counter pain relievers, antihistamines, and hot showers/baths can help you while you're healing from CHS. If you're addicted to marijuana and need help quitting, tell your doctor or call the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 800-662-HELP (4357).

Do people recover from CHS?

Yes, most do, as long as they stop using marijuana. In one small study of eight patients hospitalized with CHS, four of the five who stopped using weed recovered from CHS. The three who continued to smoke continued to have CHS. One of the 4 who recovered went back to using marijuana and the vomiting resumed.

How long does CHS last after quitting weed?

The symptoms typically last a few weeks, though the throwing up should ease up in a day or two.