A Pittsburgh Public Schools spokeswoman says 33 students were cited by school police for underage drinking at the Allderdice High School prom.
The prom was held Thursday night and one of the students became ill and had to be hospitalized. District spokeswoman Ebony Pugh says the girl has been released from the hospital.
Pugh says the other 32 students all arrived at the prom in a bus rented by a parent whom she wouldn't identify.
The prom was held at a union hall on the city's South Side. Pugh says school security officers say none of the students appeared intoxicated when they arrived at 7 p.m. but many began to show signs they were drunk as the night wore on.
Parents were called to take the students home.