Providence Police added extra officers.
The Dunkin Donuts Center added security and rescue crews.
Their concern at the Barstool Blackout foam dance party Friday night was over the drug molly and alcohol use.
Molly is a variant of ecstasy that has been blamed for several recent overdoses around the country.
As of 11pm, Dunkin Donuts Center officials reported 12 people being transported by ambulances from the venue - 10 for alcohol, 1 for admitted molly use, and one case was of unknown origin.
Just before midnight, as the foam party was about to end, Providence Police Chief Hugh Clements said there had been an arrest for suspected molly delivery and another for suspected molly possession outside the arena, and three concert-goers were arrested for public drinking on a nearby street.
There were no arrests inside the event.
Overall, Clements called the evening "tame." He expected more ambulance runs.
Some area colleges, like Salve Regina, warned students about attending the event, which drew an on-line response from the head of Barstool Sports, which put the party on, saying "do you think it makes any sense pointing the blame at our event as opposed to putting the responsibility on the students? As far as I know we've never put 1 drink or drug in a kid's mouth."