A JUNIOR prom in Massachusetts was shut down early Friday night over concerns about students eating pot-laced brownies before the event.

myFOXboston.com reported Video footage posted on YouTube showed the abrupt end to the North Andover High School event.

Warning: the video contains strong language

Four students fell ill during the prom, and it was discovered that they had eaten pot-laced brownies before leaving the high school for the event, which was held in Atkinson, N.H. As a result, the prom was shut down an hour early, at 10:00pm.

Paramedics were called and three students were taken to the Lawrence General Hospital for treatment before later being released.

Inquiries determined that 19 brownies had been distributed by a student earlier in the day before the prom.

Police in North Andover, about 48km north of Boston, are investigating.

Originally published as Pot-laced brownies shut down junior prom