Cannabinoid hyperemesis syndrome

Kə-ˈna-bə-ˌnȯid hahy-per-em-uh-sis sin-drohm | Noun

A condition in which a cannabis consumer becomes nauseated after prolonged cannabis use. The user also may experience other symptoms including vomiting and abdominal pain. Cannabinoid hyperemesis syndrome, or CHS, is episodic, with symptoms lasting for 24 to 48 hours and not returning for several weeks or months. Vomiting can be severe and leave CHS patients extremely dehydrated. CHS is a rare condition that occurs more in long-time, daily users of cannabis. Because cannabis is usually known to help keep nausea and vomiting at bay, these users may consume more cannabis once symptoms of CHS present.


“Taking a hot bath may ease the symptoms of cannabinoid hyperemesis syndrome, but quitting cannabis use will stop them entirely.”


“My friend thinks I may have cannabinoid hyperemesis syndrome; I’ll vomit a lot for two days, but then I’m fine. When I smoke it comes back again.”

More about Cannabinoid Hyperemesis Syndrome

Though rare, cannabinoid hyperemesis syndrome (CHS) occurs because of overstimulation of the endocannabinoid system, mainly the cannabinoid receptors CB1 and CB2. While cannabis often has the opposite effects of CHS (it relieves nausea, particularly in chemotherapy patients), it may negatively affect users’ gastrointestinal motility. Selective breeding for plants that produce vast quantities of THC has led to the increased prevalence of high-potency cannabis products in recent years. Higher potency products are not only associated with an increased risk for CHS, but also an increased risk for psychosis, and Cannabis Use Disorder.

The prevalence of CHS is unknown and it is often misdiagnosed. Because the condition was discovered less than two decades ago, CHS research is somewhat sparse.

Causes of Cannabinoid Hyperemesis Syndrome


Scientists have identified many potential causes for CHS, and the exact mechanisms behind this disorder are poorly understood.


One potential cause of CHS has to do with cannabis’ interaction with the gastrointestinal tract. Although cannabis primarily produces its effects by binding to receptors in the brain, the digestive tract is also sensitive to THC and the other molecules found in cannabis. With daily, prolonged use, cannabis can negatively impact the timing of nutrients moving through the digestive tract. Essentially, the brain may be getting conflicting signals from the brainstem and the gut, resulting in nausea.


Infrequent or short-term use of cannabis typically does not trigger CHS. Prolonged or intense stimulation of the endocannabinoid system (with daily use and/or high potency products) is far more likely to trigger CHS.

Symptoms of Cannabinoid Hyperemesis Syndrome


Vomiting episodes associated with cannabinoid hyperemesis syndrome can last up to 48 hours at a time and occur up to 20 times per day. Severe nausea and vomiting may be accompanied by abdominal pain. Excessive periods of vomiting can lead to dehydration, electrolyte loss, and a general feeling of disorientation. It’s important to note that CHS is far from the only condition that induces cyclic vomiting and nausea, but there are certain factors that can help determine whether this cannabis-induced syndrome is the culprit behind these symptoms.


Because CHS symptoms are separated by asymptomatic periods, they are recognized in three main stages outside of inter-episodic phases of wellness: the prodromal phase, the hyperemetic phase, and the recovery phase.

Prodromal phase

This is the beginning stage of CHS. Many cannabis users will begin to develop abdominal pain and early morning nausea, using more cannabis in an attempt to alleviate symptoms. Vomiting does not occur, even if there is a fear of vomiting, and users continue to eat normally and can take medications orally. The prodromal phase may last for several months or even years before moving to the second stage.

Hyperemetic phase

Ongoing nausea is apparent in the hyperemetic phase while vomiting episodes begin. Abdominal pain, which is present in most cases, continues. Vomiting may be severe enough to warrant seeking medical attention, potentially leading to a correct diagnosis of CHS. Cannabis users in the hyperemetic phase of CHS decrease their food intake, which may cause weight loss and dehydration. Stopping cannabis use stops the hyperemetic phase.

Recovery phase

Once a person experiencing CHS stops using marijuana, their symptoms subside and appetite returns. They may come back if he or she attempts to use marijuana again. Certain triggers, such as noxious stress, infections, or menstrual periods, may also lead users from recovery back to the prodromal phase.

Diagnosing Cannabinoid Hyperemesis Syndrome


Although often misdiagnosed, if symptoms of CHS are present and no other underlying cause is responsible for the vomiting or nausea, physicians may look to how often and how much cannabis is used by the patient.Be honest with your doctor about your cannabis use. Daily use and/or high doses of cannabis are more likely to cause CHS, but a physical exam is often required.


Currently, the only surefire method that physicians can use to distinguish CHS from other potential illnesses is by observing how the patient’s symptoms respond to heat or topical capsaicin. Other tests may be performed to confirm the cause of vomiting, such as a pregnancy test, since CHS symptoms can mimic some early pregnancy symptoms; a blood test for anemia or infection; a drug screen; and a urine analysis. An abdominal CT scan or X-rays may be ordered to determine that there is no serious issue, such as a blockage or other need for surgery.


85% of physicians do not receive education about the endocannabinoid system or cannabis’ effects on the brain and body. Because doctors have limited awareness of CHS, it may be difficult for a provider to diagnose and treat. Cyclical vomiting syndrome (CVS) causes similar symptoms. Expensive and non-diagnostic imaging scans for CHS symptoms are usually unnecessary, and the administration of opioids for treatment is controversial — the latter may even exacerbate symptoms. But remember, the only proven indicators that determine whether a patient has CHS is if the symptoms respond to heat and/or cannabis cessation.   

Criteria for CHS diagnosis


The following criteria can help lead to an accurate CHS diagnosis and management of symptoms, and reduce the need for unnecessary and expensive medical testing. To be diagnosed with CHS, a patient must be a chronic cannabis user younger than age 50 who:

  • Experiences cyclical episodes of severe nausea, vomiting, and abdominal pain, with cycles lasting on average 3 days;
  • Has delayed gastric emptying;
  • Has lost over 10 pounds;
  • Feels relatively well between cyclical episodes and eats normally;
  • Does not respond to conventional antiemetic (anti-nausea) or analgesic (painkiller) treatments, but symptoms are relieved after hot baths or showers;
  • Has no apparent organic cause for the symptoms; and
  • No longer experiences CHS symptoms once stopping cannabis use.

Treatment of Cannabinoid Hyperemesis Syndrome


Anti-nausea treatments, either over-the-counter or by prescription, typically are not useful for the treatment of cannabinoid hyperemesis syndrome. However, nausea and vomiting my subside if the user takes a bath or hot shower, or applies a capsaicin topical cream to their abdomen.


Relief from very hot water (more than 105 degrees Fahrenheit) occurs because of a peripheral tissue receptor, TRPV1, which is a critical component of the endocannabinoid system and is the only known capsaicin receptor. Hot bathing may become a learned behavior and compulsive in CHS patients. Relief by hot showering or bathing is reported in about 60% of people with CHS.


In some case studies, antipsychotics such as haloperidol have been shown to relieve CHS symptoms. Other treatments include extensive rehydration with intravenous fluids and the use of proton pump inhibitors, which reduce stomach acid production. However, stopping cannabis use is the only long-term proven treatment of CHS.


If a cannabis user has experienced severe vomiting, he or she may need hospitalization for treatment of dehydration or stomach inflammation. Electrolyte depletion can lead to serious complications such as seizures, kidney failure, shock, and brain swelling. CHS, therefore, can become a contributing factor to death in a cannabis user.


Cannabis users who have had extended periods of vomiting for a day or longer should contact their healthcare provider or visit an urgent care facility immediately and stop cannabis use if they suspect their symptoms are related to CHS.

Prevention of Cannabinoid Hyperemesis Syndrome


It isn’t entirely known what causes some people to experience the symptoms of CHS while others do not. Some users may be predisposed to CHS — with the typical antiemetic effects of THC outweighed by its pro-emetic effect in the gut — while the accumulation of THC in long-term cannabis users may increase the risk of CHS. Plenty of regular, long-term, and higher-quantity users of cannabis do not report CHS symptoms. However, it may take years for CHS to develop.


Most cases of CHS have been shown to occur with at least weekly cannabis use (others, about 20 days per month), and about 75% of those patients have used cannabis regularly for more than a year. More than 70% of CHS sufferers also are men.


And although relatively small, when one recent survey of patients experiencing CHS symptoms is extracted to the general population, it is possible that about 2.75 million Americans may suffer from CHS. The best way to prevent CHS is to use cannabis in moderation. High doses, frequent use, and high-potency THC products are the biggest risk factors for developing CHS.