U.S. Poison Control Centers are reporting an increase in calls related to marijuana and other natural psychoactive substances such as jimson weed and hallucinogenic mushrooms, according to HealthDay.

Exposure to these substances led to more than 67,300 calls over almost two decades. The substances most commonly involved were marijuana (47%), anticholinergic plants such as jimson weed (21%), and hallucinogenic mushrooms (16%).

Hospital admissions and serious medical outcomes were most commonly linked with kratom, khat, jimson weed and hallucinogenic mushrooms, researchers report in Clinical Toxicology.

“These substances have been associated with a variety of serious medical outcomes including seizures and coma in adults and children,” study co-author Henry Spiller said in a news release. “As more states continue to legalize marijuana in various forms, parents and health care providers should treat it like any other medication: locked up, away, and out of sight of children.”