Evanston Township High School officials say a half-dozen students became ill at school recently and some were hospitalized after they ate home-made brownies laced with marijuana.
In a letter to parents School Superintendent Eric Witherspoon says the brownies, which had a large amount of marijuana in them, were baked by a student who brought them to the school.
He says it appears the students involved knew what they were eating.
Witherspoon said the incident has been referred to police.
An Evanston police spokesman says one student, a 17-year-old male, has been charged as a juvenile with possession of cannabis in connection with the Feb. 1 incident. He says four students were taken to local hospitals and one declined treatment.
The superintendent said the students will face school discipline for breaking substance-abuse rules, and, if appropriate, extracurricular code sanctions.
In the letter Witherspoon urged parents to warn their children about accepting homemade baked goods from others and to talk to them about the dangers of drug use and the legal problems they can face as a result.
He said parents with concerns about the issue could contact the school's student assistance services coordinator, Cristina Cortesi, at 847-424-7580.