11/03/2014 06:15 EST | Updated 01/03/2015 05:59 EST

Brett Belchetz says 'nobody knows' contents of party drugs

A Toronto emergency room doctor is warning the public about the dangers posed by so-called party drugs, following a weekend in which three young people nearly died from ingesting them.

Dr. Brett Belchetz said that at the start of his shift on Saturday, he was told that a rave was taking place in the community and that he should expect to see patients admitted during the night.

"Unfortunately, those predictions proved to be true," he said in an interview on Monday.

Belchetz told CBC News that six such patients were admitted after taking party drugs and three nearly died.

"Three of those teenagers had ingested so much of varying different kinds of drugs that they were actually unconscious to the point that they weren't breathing effectively anymore," he said.

In August, two young people died at the Veld Music Festival after ingesting what police believe were party drugs — such as MDMA or GHB, the date-rape drug. More than a dozen others fell ill at the same event.

Belchetz said that when his patients are screened for drugs, he never finds that that it is just one drug in their system.

"It's not that these people were doing multiple different drugs, it's that nobody knows what's in the drugs they're taking, so they can take one pill that is cut with four or five different substances," he said.

Belchetz suggests it may be time to put in a place a system to permit pill-testing at events — as it may be impossible to stop pills from being brought into a venue, but at least it would be possible to prevent future deaths.

Click on the video above to see a full report from the CBC's Michelle Cheung.