When several preschool teachers in Los Angeles fell sick last April after eating brownies, public health investigators suspected it wasn’t a typical case of food poisoning. The symptoms included giddiness, dizziness, mood changes, dry mouth  and a bad case of the munchies.

One of the teachers had bought the homemade goodies a few days earlier from what she thought was a church bake sale; she shared them with colleagues during a work break.

But within 90 minutes of eating just one brownie each, five teachers became ill; the adult son of the buyer also reported symptoms.

It turned out there had been no church bake sale. And a leftover piece of brownie tested positive for cannabinoids found in marijuana, according to a report of the incident published Sept. 4 in The Morbidity and Mortality Weekly Report of the Centers for Disease Control and Prevention.