A mystery drug has the Regina Police Service warning the public about the risk of overdoses, as investigators scramble to figure out what it is.

On Thursday, two men were taken to hospital after overdosing on a drug they believed was heroin.

The drug is being tested right now, and it's not clear what the substance was.

While the overdoses were non-fatal, and the men have since been released from hospital, police are warning the drug-using community to be cautious about any potential heroin being sold in the city.

An investigator is consulting with police drug experts to track where the drug may have come from.

Anyone with information is asked to call Crime Stoppers at 1-800-222-8477, or the Regina city police at 306-777-6500.