The Regina Police Service has issued a warning about a potentially fatal drug after two men overdosed on an unknown substance.

Two men, ages 41 and 47 were taken to hospital from a house on the 1800 block of Osler Street after overdosing on the morning of June 22.

Both men have since been discharged from the hospital.

According to police, the men believed they were using heroin, but investigators are still conducting an investigation to determine what the drug actually was.

Police are warning members of the public, especially those with drug dependencies, to take extra precautions while they determine what the substance was and where it originated from.

Anyone with information about the substance is asked to call Regina Police at 306-777-6500 or Crime Stoppers at 1-800-222-8477. In an emergency, please dial 911.