Wellington County OPP say one person is in life-threatening condition following a crash near Belwood Lake on Wednesday evening.
Emergency crews were called to Wellington Road 16 at about 5:30 p.m. for reports of a crash between a pickup truck and a minivan.
Police said five patients were treated by paramedics and a 31-year-old driver was transported to a trauma centre in life-threatening condition.
The road was closed through the night for the investigation.
Anyone who witnessed the crash or has dashcam video is asked to call investigators at 1-888-310-1122.