Let’s imagine that one day you feel a sudden pain in your belly. That pain is accompanied by a nausea so bad that you totally lose your appetite. Later, you start vomiting incessantly. It doesn’t seem to be anything you ate, and you have no idea what caused it.

Desperate for relief, many cannabis users might reach for a joint, a cannabis tincture, or CBD oil. After all, research has shown us that cannabis has anti-nausea, pain-relieving, and appetite-stimulating abilities.

But what if cannabis isn’t the best cure? What if it’s the cause?

Cannabis hyperemesis syndrome is a poorly-understood condition. But, as cannabis becomes legal in more places around the world, it’s crucial to understand more about it.

The symptoms of cannabis hyperemesis syndrome include extreme vomiting, nausea, and loss of appetite. The symptoms last between 24-48 hours, but they might return if you continue to use cannabis. If left untreated, it can lead to dehydration and renal failure—and the only way to treat it is to stop consuming cannabis products, even if only temporarily.

Many people don’t believe the condition really exists. After all, governments have had a long history of exaggerating and even fabricating the risks of using cannabis. So it’s understandable that many activists think the condition is invented to undermine legalization efforts. The condition was first recorded in a 2004 paper, and in 2006 the paper was criticized for poor study design.

So, it’s understandable that some cannabis users and activists are wary of the concept of CHS. But as more and more cannabis research is conducted, we’re beginning to see that it is indeed a real thing.

It’s possible to experience cannabis hyperemesis symptoms after using it for years without any problem. In fact, a 2014 article suggests that the condition is actually caused by chronic cannabis use.

A 2011 paper detailed how one man was admitted to hospital after experiencing extreme stomach pain, nausea, and vomiting. Eventually, he was diagnosed with cannabis hyperemesis syndrome.

Similarly, cannabis advocate Alice Moon was diagnosed with cannabis hyperemesis syndrome in mid-2018. According to RxLeaf, Moon used cannabis products for many years. She started experiencing extreme nausea and vomiting, and after eliminating certain foods from her diet, she realized cannabis was the culprit.

So, what helps people with cannabis hyperemesis syndrome? Heat. In the 2011 paper mentioned above, it was noted that prolonged, hot showers eased the patient’s symptoms. Other research notes that people with the condition tend to take hot baths or showers because it seems to bring them relief. Topical capsaicin—yup, pepper extract—seems to soothe the symptoms.

This is because the condition might be caused by overstimulating the TRPV1 receptor in our brain. This receptor is stimulated by heat, peppers, and cannabis. The idea is that the TRPV1 gets overstimulated, it shuts down. The brain responds to this by causing frequent vomiting.

That’s just one possible explanation for what causes cannabis hyperemesis syndrome. It could be caused by a cannabinoid overload, or a reaction to pesticides caused by growing practices, or something else. Unfortunately, more studies need to be done before we totally understand what causes it.

If you think you might have cannabis hyperemesis syndrome, stop using cannabis for a while. Within a week, your symptoms will start easing up, according to the research. Speak to a doctor about your symptoms. For short-term symptom relief, hot showers and warm compresses might help.

Scientific research has shown us that cannabis has a range of healing powers and that it can help many people. But we also can’t ignore the limitations of the plant, nor can we ignore the fact that it coult harm some people. After all, cannabis is a form of medicine and, as with all forms of medicine, cannabis can have side effects.

There’s still a lot that we don’t know about cannabis hyperemesis syndrome. But for now, it’s worth noting that it does exist, and it can be fatal. When it comes to your health, it’s always best to err on the side of caution and stay informed about conditions that might affect you.


Sian is a writer, journalist and editor who covers cannabis, health, and social justice. Her work can be found on HealthlineTeen VogueEveryday FeminismHealthyWayand HelloGiggles. Visit her website or follow her on Twitter.