The Nishnawbe Aski Police Service is issuing a warning about toxic drugs in the communities it serves.
NAPS says it has seen a significant spike in opioid-releated overdoses, especially in the northeast region this month.
Some of the recent incidents have been fatal.
Police say often fentanyl is used as a cutting agent for other drugs and can often be made more dangerous.
Investigators say they can’t provide a description of the drug suspected of causing the overdoses because traffickers can change the colour of their product.
NAPS is also encouraging community members to keep a supply of Naloxone on hand for suspected opioid related overdoses.