In one of the cases, a 16-year-old girl was found naked and unconscious and hospital tests found that she had consumed the so-called date rape drug GHB.
Martin Fournel of MRC des Collines police said investigators have yet to confirm what happened between the time the girl fell unconscious and the time she was found.
He says victim services are working with the girl.
"The individual involved doesn't remember anything because of the drug," he said. "So we need to verify some information and validate some information.
"Obviously it's not pleasant for her and her parents."
In the other case, a 17-year-old girl reported being inappropriately touched on her way into the party.
Friday's "Spookland" event resulted in nine party-goers between the ages of 15 and 17 — six girls and three boys — being transported to hospital for drug or alcohol-related illnesses, according to police.
Authorities initially said 12 people had to be hospitalized.
One boy fell into a coma with a blood-alcohol content six times higher than the 0.08 level.
"I think we're lucky he's still alive," said Fournel.
The party was billed as an event for students between 16 and 21 years old and Fournel says police are looking into whether the bar was serving alcohol to minors or serving patrons already intoxicated.
It was the third edition of the "Spookland" event.
Fournel says many partiers were already under the influence of drugs or alcohol when they arrived at the event after taking bus rides from various Ottawa communities.
Security checks at the door of the party resulted in the seizure of "lots of alcohol," he said.