As the number of marijuana smokers in the US continues to rise, so does the number of reports for a strange condition that can only be relieved by taking hot showers (or by stopping smoking pot, obviously).

The symptoms of the condition include cyclic bouts of nausea, vomiting, and severe abdominal pain, which is not prevented or helped by anti-nausea pills. It seems the only relief from the syndrome is taking a hot bath or shower, which soothes the condition for a short while, until it returns not long after.  

The condition arises in people who are heavy marijuana smokers (defined as puffing on weed at least 20 days per month), and is technically known as cannabinoid hyperemesis syndrome (CHS). The study, published in Basic & Clinical Pharmacology & Toxicology, was based on 155 heavy marijuana users, 33 percent of whom experienced CHS.

While people presenting with the symptoms of the condition used to be a rare occasion, doctors are increasingly treating patients with CHS, according to The New York Times. This observation is supported by the study that found that up to a third of heavy pot smokers might be experiencing it. That translates into a potential 2.75 million sufferers in America, although there may be other factors in play as well.

Despite being fairly prevalent, we know surprisingly little about the condition. While we know the heavy use of weed triggers it and that a hot shower relieves it, the cause of CHS is a head-scratcher. However, there are a couple of working theories.

We know, for example, that the body’s system for dealing with pain includes endogenous cannabinoids. This is thought to be one of the reasons why smoking pot helps to dampen pain in some patients, as the tetrahydrocannabinol in marijuana interacts with this system. But some doctors think that triggering this pain system too frequently disturbs it and induces CHS

One doctor told Live Science that he thinks that over-stimulation of the pain system could be having a negative effect and that the hot shower is simply a way of distracting the brain by producing a different sensory signal, and hence relieving the pain.

It is important to stress that this theory is not certain, but a hypothesis. Doctors still don’t fully understand the condition, why some people get it and some don’t, and why it can be used to treat nausea in patients undergoing chemo but seems to induce it in others. 

What is certain, though, is the simple way to prevent the nausea and stomach cramps if you do develop CHS – stop smoking pot.