The U.S. Food and Drug Administration has issued a warning to the maker of the ‘relaxation brownie’ to stop production, saying the brownies have unsafe additives, the Associated Press is reporting.

The federal agency issued the warning to HBBC, based in Memphis, that the melatonin in the brownies hasn’t been deemed a safe additive. If the company continues to make them, regulators could snatch them from shelves. Larry Cakes, formerly sold under the name Lazy Cakes, are sold throughout the Lake Norman area.

Melatonin is a naturally occurring hormone that helps people fall asleep. The brownies can cause “extreme relaxation,” according to its label.

The Center for Carolinas Poison Center told National Public Radio earlier this year that eating an entire Larry Cake could be twice the recommended dose of melatonin.