Toronto EMS says they have transported 10 people to hospital from the Avicii concert at the Rogers Centre Saturday night.
Toronto EMS Commander Peter Rotolo told CP24 that before the concern even started, they began to recieve 911 calls to treat people who "overdosed" on alcohol.
The city's paramedics were not requested to be on stand-by at the sold-out concert, Rotolo said, but were called in when private medical professionals became "overwhelmed."
One arrest has been made in connection with the incident.