For more than two years, Lance Crowder was having severe abdominal pain and vomiting, and no local doctor could figure out why. Finally, an emergency room physician in Indianapolis had an idea. “The first question he asked was if I was taking hot showers to find relief. When he asked me that question, I basically fell into tears because I knew he had an answer,” Crowder said. The answer was cannabinoid hyperemesis syndrome, or CHS. It’s caused by heavy, long-term use of various forms of marijuana. For unclear reasons, the nausea and vomiting are relieved by hot showers or baths. “They’ll often present to the emergency department three, four, five different times before we can sort this out,” said Dr. Kennon Heard, an emergency room physician in Aurora, Colorado. He co-authored a study showing that since 2009, when medical marijuana became widely available, emergency room visits diagnoses for CHS in two Colorado hospitals nearly doubled. In 2012, the state legalized recreational marijuana. “It is certainly something that, before legalization, we almost never saw,” Heard said. “Now we are seeing it quite frequently.” Outside of Colorado, when patients do end up in an emergency room, the diagnosis is often missed. Partly because doctors don’t know about CHS, and partly because patients don’t want to admit to using a substance that’s illegal. CHS can lead to dehydration and kidney failure, but usually resolves within days of stopping drug use. That’s what happened with Crowder, who has been off all forms of marijuana for seven months. “Now all kinds of ambition has come back. I desire so much more in life and, at 37 years old, it’s a little late to do it, but better now than never,”he said. CHS has only been recognized for about the past decade, and nobody knows exactly how many people suffer from it. But as more states move towards the legalization of marijuana, emergency room physicians like Dr. Heard are eager to make sure both doctors and patients have CHS on their radar.