An air ambulance was called in after two vehicles collided head-on, injuring both drivers.
West Grey Police say it happened Monday on Grey Road 4 east of Durham, about 25 kilometres north of Mount Forest.
According to police, one vehicle slid into the path of the other vehicle.
One driver lost consciousness and was airlifted to a London hospital with serious injuries.
The other driver was also hurt, although their injuries were less severe.
Police say charges are pending.