Cannabinoid hyperemesis syndrome is a side effect of marijuana smoking that affects patients worldwide, but is unfamiliar to many clinicians.

A new study by Joseph P. Habboushe, MD, assistant professor in the Ronald O. Perelman Department of Emergency Medicine at NYU Langone Health, shows that this condition is much more prevalent than previously thought. “The big news is that it’s not a couple of thousand people who are affected—it’s a couple million people” he tells The New York Times.

With this illness, patients experience severe pain and vomiting that seems to only be relieved by taking hot showers. Dr. Habboushe expresses the need for more research especially with the politicized discussion of the drug. “No medication is free of side effects,” he says.

Read more from The New York Times.