vomiting and bathing Cannabinoid Hyperemesis Syndrome
3 min

What Is Cannabinoid Hyperemesis Syndrome?

3 min

Cannabis Hyperemesis Syndrome is a rare reaction in some heavy cannabis users. We take a look at what it is, what the symptoms are, and address how common it is to encounter amongst heavy users (hint: not very!).

Cannabinoid Hyperemesis Syndrome (CHS) is one of the few longer-term potential negative health impacts that maybe directly caused by cannabis. But is it really a thing, and should everyone be worried about it? Only if you are seriously unlucky.

CHS is a condition caused by a form of cannabinoid intolerance that can develop in longer term heavy smokers over a period of many years (smoking between 3 and 5 times a day) and is characterized by debilitating nausea and vomiting. People suffering from this condition often find that hot baths or showers significantly lessen their symptoms. As a result, many will compulsively bathe to relieve the same until they dissipate. Symptoms stop after cessation of cannabis use. The good news? It is extremely rare - even amoung heavy users.

This “compulsion” however, may in fact have a direct scientific cause. According to a government-backed study conducted in Philadelphia, “hot bathing may act by correcting the cannabis induced disequilibrium of the thermoregulatory system of the hypothalamus."

The knowledge that cannabis consumption affects the hypothalamus is not news. Cannabinoids can exert a huge impact on hypothalamic regulatory function – and are more frequently understood in scientific literature to help maintain, not undermine neuroendocrine homeostasis.

What makes CHS rare is precisely because in what appear to be a small group of individuals, the human body can suddenly become overloaded. Cannabis consumption in such cases, seems to have the opposite effect than it normally does. It means for most heavy users are unlikely to be affected.


There are several stages of what so far has still been an understudied phenomenon.

The “prodromal” phase can occur between months and years before the actual onset of severe cyclical vomiting symptoms. During this time, users feel “morning sickness,” (or early morning nausea), abdominal pain and discomfort and fear of vomiting. This apparently is also a time when cannabis users frequently increase their intake because of the common knowledge that marijuana more frequently combats such symptoms.

The “hyperemetic” phase is characterized by intensification of these sensations, along with persistent nausea and vomiting that lasts for hours at a time, weight loss, dehydration and frequent bathing.

Recovery is not immediate – it can take days, weeks or even months after the cessation of cannabis use for the symptoms to entirely dissipate. However, this is the only way to prevent reoccurrence of symptoms. People who have had one experience with CHS experience relapses soon after cannabinoid consumption.


The answer is no. It is rare. Pennsylvania study authors also found that average use of cannabis before onset of symptoms was 16 years, with the earliest onset developed in a patient after three years of heavy use. A 2004 study in Australia also noted that cases only occurred in heavier pot users over at least a period of years and in an environment where marijuana was easily accessible.

In both the Australian case and in anecdotal evidence beginning to present itself in American states where recreational use has become legal, one reason for the condition may be that more people are in fact, smoking marijuana. However, even with the dramatic uptick in legal users, instances of CHS are still extremely rare.


Sadly, the answer to this one is no. In fact the only known cure for the condition at this juncture is immediate and permanent cessation of cannabis usage.

It is unknown, because the study authors did not appear to ask the question, whether study participants considered themselves “casual” or “medical” users and or if there was an underlying medical reason for such regular and heavy use.


The good news is that this phenomenon has only been seemingly “discovered” over the past decade or so – and further at a time when cannabis use is increasing. As a critic of the 2004 Australian study noted several years later, “Cannabis has been consumed for many centuries and is currently used by millions of people in many countries. It is hard to believe that a distinctive syndrome caused by cannabis has never been noted before by users or clinicians.”

As this study noted, as well as other people who are sceptical about the real causes of the condition, it could be that such reactions are actually caused by something other than cannabinoids – in other words pesticides or other chemicals added during the growth, harvesting or curing process.

Another theory is that it could be the way marijuana is consumed. Some sufferers have reported such symptoms after consuming a powerful concentrate or high-dose edible.

It could be that the antiemetic qualities of the drug on the brain are overridden in certain individuals susceptible to the condition by an emetic effect on the gut.

However, this idea has never been clinically examined or studied. The Australian study, which came to the same general conclusions about cause and progression of the condition, also noted that all of the people they studied smoked cannabis itself rather than an extract.

Adam Parsons
Adam Parsons
Professional cannabis journalist, copywriter, and author Adam Parsons is a long-time staff member of Zamnesia. Tasked with covering a wide range of topics from CBD to psychedelics and everything in between, Adam creates blog posts, guides, and explores an ever-growing range of products.
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