Cannabis Hyperemesis Syndrome: Things to Know

Understanding the rare condition

Cannabis is the most-used recreational drug in the USA, and in recent years it has received a lot of publicity for its possible medical applications. Clinical studies have shown that cannabis may relieve the symptoms of a variety of conditions ranging from chronic pain to anxiety, and it is reported to be safe with a low risk of side effects.

Although in most cases this is true, cannabis is not always entirely free from adverse effects. Since marijuana has been decriminalized in certain states, its use is becoming more mainstream and emergency rooms are seeing a sharp increase in patients with cannabis hyperemesis syndrome (CHS).

But what is cannabis hyperemesis syndrome, and how can you ensure that you aren’t at risk?

What is Cannabis Hyperemesis Syndrome?

CHS was first recognized as a medical condition back in 2004. It affects some, but not all, long-term or heavy cannabis users, causing recurrent episodes of severe nausea and vomiting. These episodes may last for several days, and patients with CHS often end up hospitalized, vomiting up to five times an hour without relief. These people are often seriously dehydrated, but laboratory tests and other investigations show no physical reason for the symptoms.

Nausea and vomiting usually subside after 24–48 hours, but may last for as long as 7–10 days. After this, there will be a symptom-free period of days, weeks, or even months during which time the person is able to eat and function normally. However, unless they stop using marijuana altogether, there is a high risk of the symptoms returning sooner or later.

What Causes Cannabis Hyperemesis Syndrome?

The exact reason why some people suffer from CHS is unclear. The condition is especially puzzling considering that one of the common medicinal uses of marijuana is in the treatment of nausea and vomiting.

How can something which is used to relieve sickness cause it too? It seems the answer may lie within the endocannabinoid system.

The endocannabinoid system is found in all animals and is made up of receptors known as CB1 and CB2 receptors. These are designed to interact with chemicals produced by our own bodies, but they also react to the compounds found in cannabis. The majority of CB1 receptors are found in the brain, nervous system, and the digestive tract as well as other organs, whereas most CB2 receptors are found in the immune system. It is CB1 receptors which are thought to be responsible for cannabis’ ability to both relieve and cause nausea.

Three of the compounds in cannabis, tetrahydrocannabinol (THC), cannabigerol (CBG), and cannabidiol (CBD) are thought to play a role in this mechanism. It appears that THC reacts with CB1 receptors in a way that reduces nausea, while CBG has the opposite effect. CBD seems to relieve nausea in low doses, but may also induce it if too much is consumed.

It can take years of chronic cannabis use for the symptoms of CHS to appear, and it has been suggested that after this long spent time getting high, there could be changes in the way these receptors signal to the brain. CHS is much more common in males than females, and there may also be a genetic factor at play, explaining why only a small proportion of long-term marijuana users go on to develop the syndrome.

Symptoms of Cannabis Hyperemesis Syndrome

The pattern of CHS follows three distinct phases: prodromal, hyperemesis, and recovery.

In the prodromal phase, patients may experience abdominal discomfort and frequent nausea, especially in the early mornings. They may feel like they want to throw up, but not actually do so. This phase can last for months or even years before progressing to hyperemesis.

Once the hyperemesis phase begins, CHS sufferers will feel constantly nauseous and vomit several times an hour. This phase can be completely debilitating and also leads to severe dehydration and weight loss. Hyperemesis is the stage where patients could end up hospitalized, receiving intravenous (IV) fluids and being monitored closely. The hyperemesis phase of CHS usually lasts a couple of days, but can go on for as long as a week or more.

Finally, the recovery phase begins. The patient is gradually able to start eating normally and can regain any lost weight and return to their regular, daily routine. The recovery period can last for days, weeks, or months before the cycle repeats itself again.

Treatment of Cannabis Hyperemesis Syndrome

If you are a pot-smoker unlucky enough to suffer from CHS, what can you do to help yourself?

Unfortunately, the only way to guarantee a complete recovery is to stop using marijuana entirely. Many people find this extremely difficult, and some CHS sufferers even try increasing their cannabis intake, having heard that it can relieve nausea. However, in these cases, it will likely only make the problem worse.

If you do decide to quit cannabis, it can take 7–10 days for the symptoms of CHS to go away completely, so you will need both patience and willpower for this. If you have CHS and are unable or unwilling to stop using cannabis, here are a few solutions which may help to relieve your symptoms in the short-term:


The most commonly prescribed medications for nausea and vomiting are antiemetics. These include several different classes of drugs which are targeted to relieve these particular symptoms. They can be administered by mouth or via IV drip if the patient is unable to hold anything down. However, in CHS, these medications appear to have little to no effect, and are therefore of limited use for this condition.

Other drugs such as benzodiazepines (lorazepam, diazepam, etc.) may be used to reduce abdominal pain during the hyperemesis phase. These should only be used as a short-term solution due to the high risk of dependence, and opioid painkillers should be completely avoided for the same reason.

Hot Water Bathing

One common practice among people with CHS is bathing or showering in very hot water during the hyperemesis phase. Doing this temporarily alleviates the symptoms, and sufferers have reported staying in the shower for prolonged periods, desperately seeking some relief.

Scientists believe that the simple action of putting hot water onto the skin stimulates receptors known as vanilloid (TRPV1) receptors. These receptors play a role in the transmission of pain signals and controlling movement in the digestive tract. It is thought that long-term exposure to cannabinoids may block these receptors, resulting in the symptoms of abdominal pain, nausea, and vomiting seen in CHS. High temperatures can reverse this effect, and many CHS sufferers quickly learn that taking a hot shower helps.

If you want to try hot water bathing to reduce your CHS symptoms, it is important to take care not to scald yourself. Check the temperature of your water before getting in, and do not stay under very hot water for too long, or nausea could be the least of your worries!

Capsaicin Cream

An alternative to hot water bathing which works in a similar way, is capsaicin cream. Capsaicin is the chemical found in chili peppers which makes them hot. This compound can be extracted and made into a concentrated cream which is rubbed onto the skin to relieve pain.

It is commonly prescribed for conditions such as arthritis, but a recent case study has shown that it could also be effective in reducing the symptoms of CHS. In this study, capsaicin 0.075% cream was applied to a 15x25cm area of skin on the lower abdominal area every four hours. After four doses, the patient reported complete resolution of his abdominal pain and nausea.

Capsaicin cream causes a warming or burning sensation on the skin, which is how it is thought to relieve the symptoms of CHS. In some people, this cream can cause a rash, so you should test it out on a smaller patch of skin first to see how you react. Wash your hands thoroughly after applying the cream, and avoid contact with your eyes, nose, mouth or genitals. Capsaicin should not be used on damaged or broken skin.


If you have CHS, you could be vomiting many times a day, leading to severe dehydration. This situation can be dangerous, and you should make every effort to keep some fluids down. Rehydration salts mixed with water or sports drinks containing electrolytes are best. Try taking small, regular sips to reduce the chance of them coming straight back up.

If you are unable to hold any food or water down, you should visit your local hospital where you will be given IV fluids and possibly other medication to relieve your symptoms.

Final Thoughts on Cannabis Hyperemesis Syndrome

CHS only affects a small proportion of cannabis users, but it can be a debilitating condition, causing significant interruptions to daily life and lost work days. It is a cyclical syndrome, meaning that there are long symptom-free periods, alternating with severe nausea and vomiting which can last for several days.

The only way to completely reverse the syndrome is by stopping marijuana use, but for many sufferers, this is a difficult decision to make.

Cannabis laws are now being relaxed in many places, and the use of marijuana is as popular as ever. It looks like CHS is something which is not likely to disappear any time soon, and every regular smoker should be familiar with its symptoms.

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