There has been an increase in the number of cases of a rare, mysterious, and potentially dangerous illness linked to cannabis use. An ABC News investigation found that despite the widespread belief that using cannabis is harmless, some people develop a condition called CHS, or cannabinoid hyperemesis syndrome, after consuming high concentrations over long periods of time.

According to Good Morning America, this rare illness is being reported more often as marijuana is legalized and higher potencies are available. One victim, a healthy 33-year-old named Erica Hagler, used cannabis several times a day when she was struck by CHS. She recalls thinking she was going to die, adding that her symptoms included “the shakes, elevated heart rate, completely dehydrated and the vomiting was back-to-back.”

Initially, she was misdiagnosed by doctors until she researched CHS and diagnosed herself. This rare condition causes bouts of vomiting and abdominal pain. A Canadian study found that CHS-related emergency room visits increased 13-fold from 2014 to 2021.

“One challenge we have is that patients sometimes believe that their use of marijuana is helping them,” said Dr. Sam Torbati, co-chair of the department of emergency medicine at Cedars-Sinai Medical Center. “We know that in patients with cancer, marijuana actually reduces nausea and vomiting — so for many patients, understanding that for them this is poison — is a tough pill to swallow.”

Torbati says that patients are given intravenous fluids to hydrate them and basic testing to evaluate kidney health and electrolyte balance. But to cure this condition, they must stop smoking. Hagler has been cannabis-free for five years, says GMA, and started a Facebook group, CHS Recovery, that has 20,000 members.

According to Cedars-Sinai, marijuana has several active substances, including THC. The compounds bind to molecules found in the brain that trigger the drug “high,” as well as other effects on the body. The digestive tract has several molecules that also bind to THC, so marijuana affects the digestive tract as well.

While marijuana can help the brain calm nausea and vomiting, it can have the opposite effect in the digestive tract. It can make you more likely to have nausea and vomiting. Some heavy users develop CHS, while others don’t, and the reason is unclear. However, if the condition worsens it can cause muscle spasms, weakness, kidney failure and heart rhythm abnormalities and in very rare cases, brain swelling. Experts say that CHS can be prevented by not using marijuana in any form.