The number of young children who accidentally ingested marijuana edibles between 2017 and 2021 – a period when marijuana became legal in more states – rose sharply, AP reports.

A new study found more than 7,000 confirmed cases of children younger than 6 ingesting edibles were reported to U.S. poison control centers during that time. In 2017, about 200 cases were reported, compared with more than 3,000 in 2021. Almost one-fourth of the children were hospitalized.

Lead researcher Dr. Marit Tweet of the Southern Illinois School of Medicine said preventing children’s accidental ingestion of edibles requires more parental vigilance. She also said more states should adopt laws to make marijuana products less appealing and accessible to children.

“When it’s in a candy form or cookies, people don’t think of it in the same way as household chemicals or other things a child could get into,” she said. “But people should really be thinking of it as a medication.”