When Weed Makes You Sick

Cannabis has a long-standing reputation for soothing people’s stomachs. But despite the relief cannabis can give to patients with conditions including everything from AIDS to epilepsy, in some rare instances smoking weed can cause uncontrollable puking and stomach pain that lasts for several days.

This condition, known as cannabinoid hyperemesis syndrome (CHS), is rare, elusive, and way more than a bad high. While puking over pot may seem like a rookie move associated with smoking too much and “greening out,” CHS only occurs in excessive daily, long-term users and once it hits, many people can never go back to cannabis again.

CHS is a new and unfortunate phenomenon for cannabis fans. It’s been estimated by one study that around 2.75 million people in the US receive a CHS diagnosis annually, but this an approximate first attempt to measure its prevalence. First examples of the condition were published in the medical literature in 2004. The condition occurs in three distinct phases.

First there is the prodromal phase, where individuals experience nausea first thing in the morning, abdominal pain, and the fear of throwing up. As a result, people tend to use more cannabis to manage these symptoms, which unfortunately backfires during the hyperemetic phase, which is characterized by debilitating nausea and uncontrollable vomiting.

While some patients report that hot baths and showers provide some relief, they typically have to cease cannabis use altogether before they can enter into the recovery stage. Symptoms can take anywhere from a few days to several weeks to resolve, and excessive puking can lead to dehydration, fainting, weight loss, and kidney damage during that time.

“It’s counterintuitive that cannabis should cause nausea and until you consider that the endocannabinoid system’s role is to maintain homeostasis,” physician Dr. Jordan Tishler, medical advisor for cannabisMD. “Some cannabis can be helpful, but too much is likely harmful.”

“There may be something about too much cannabis use over time that has the potential to throw individual endocannabinoid systems completely out of whack.”

Experts are not entirely sure why CHS happens, but there may be something about too much cannabis use over time that has the potential to throw individual endocannabinoid systems completely out of whack. According to Dr. David Knox, recent data presented at this year’s CannMed conference further confirms this.

Analyzing 200 CHS patients, researchers determined that 36.5 percent of people used cannabis for more than eight years before the onset of CHS symptoms, whereas 19.5 percent used cannabis for five to eight years, 18 percent of used for three to four years, 17.5 percent used for one to two days, and only 8 percent who smoked or consumed weed for less than a year before getting sick.

CHS does not appear to be linked with more or less any particular variety of cannabis, but is more strongly associated with inhaling cannabis via smoking, vaping, or dabbing compared to edibles. Concentrates likely carry more risk due to the higher THC content. Only 50 percent of people who had CHS were able to resume cannabis use without recurring symptoms.

“Clearly, CHS occurs as a complication of cannabis use or overuse,” Knox, a physician at The Knox Docs, says. To Tishler, one possible explanation of CHS that cannabis overuse over time can cause “down-regulation” of cannabinoid receptors, or a decreased cellular response due to a decrease in the number of receptors on the cell surface, which makes it harder for the endocannabinoid system to work the way it’s supposed to.

"In Colorado, emergency room visits for cyclical vomiting have doubled since legalization. However, a growing amount of emergency rooms might be diagnosing CHS incorrectly."

While further research in the condition needs to be done overall, there is some evidence that it is more common among men (who tend to smoke more concentrated cannabis in general) and in Colorado, emergency room visits for cyclical vomiting have doubled since legalization. However, a growing amount of emergency rooms might be diagnosing CHS incorrectly.

“It’s important to know that there are a few conditions that are more prevalent that look a lot like CHS,” Tishler says. “It’s extremely uncommon and most cases that are attributed to CHS are not, in fact, CHS.”

Namely Cyclical Vomiting Syndrome, or CVS, is a much more common condition, the cause of which is unknown and not specific to cannabis. Still, plenty of people who get CVS might use cannabis to treat their symptoms, so it can be challenging to separate the two illnesses. To Tishler, the main distinction is that CHS typically takes several ER visits to accurately diagnose and that the only thing that helps treat symptoms are hot baths and showers. And yet Knox notes that, in general, plenty of nauseous people take hot baths and showers to cope.

“Transient relief of symptoms with hot baths or showers have also been thought to be pathognomonic for CHS,” Knox says. “But recent studies have shown that a fair percentage of patients with CVS and psychogenic nausea and vomiting also get relief with hot baths.”

On the flipside, in the past people who have had CHS have been misdiagnosed, partially because people have not always been honest with their doctors about how much cannabis they use, or using it at all. At least two people eventually diagnosed with CHS reportedly had their gallbladders unnecessarily removed because doctors initially did not know what they were dealing with.

As cannabis becomes legal in more states and the stigma of recreational use decreases, patients being more forthcoming about their use may help doctors develop better diagnostic criteria, along with additional research. Until then, both experts recommend seeing a doctor for anyone experiencing symptoms that might be CHS, even if it’s not.

“The risk of not getting help can lead to serious consequences, some of which may not be reversible,” Tishler warns.

But if you’re just worried about the hypothetical, consider CHS one of the many reasons to enjoy, but never abuse cannabis in the long term. Given that most CHS patients have to quit cannabis cold turkey to avoid spooning with the toilet for several days or a trip to the ER, if you’re worried, it may be worth it to consider cutting back if you’re a daily dabber, bong hitter, or friend of the vape.

No one wants to ruin the heavenly combination of cannabis and a hot bath that way.