Police in Durham region, east of Toronto, have issued a public alert following four near-fatal drug overdoses last weekend.
Over a 30-hour period, the police force says officers and paramedics were called to four locations in Whitby and Ajax-Pickering where a person had taken cocaine and became unresponsive.
In all four cases, the victims were revived, but are still in hospital.
Police say it is too early to determine what caused the reactions or if the incidents are related, but the regional force is warning the public that illegally-purchased narcotics can be mixed with dangerous additives that can have fatal consequences.
Police say illicit drug users experiencing a serious illness should call 911 or go to a local hospital immediately.
This content appears as provided to The Globe by the originating wire service. It has not been edited by Globe staff.