The incident, which left the road completely blocked, happened just before 10am on Worcester Road near to The Dog Inn.
Two people were freed from their vehicles – with one of the drivers taken to the region’s trauma unit at the Queen Elizabeth Hospital in Birmingham with serious injuries.
A second motorist was taken to Russells Hall Hospital in Dudley with potentially serious injuries.
Police also confirmed an arrest was made.
A spokesperson for West Mercia Police said of the incident: “We received a call around 9.50am this morning (December 30) with a report of a collision on Worcester Road, Harvington.
“Officers arrived to find two vehicles involved.
“One man was arrested on suspicion of drink driving.
“Another man was taken to the Queen Elizabeth Hospital with injuries.”
Hereford and Worcester Fire and Rescue Service said it sent two crews – one from Bromsgrove and one from Worcester Fire Station – after receiving an emergency call at 9.59am.
A spokesperson for the fire service said: “The incident involved two vehicles both of which were on all four wheels on the highway.
“Two casualties were extricated by fire service personnel and handed over to the care of the ambulance service who attended along with police and highways.
“Worcester Road was completely blocked.”
Fire crews left the scene at 12.24pm.
West Midlands Ambulance Service said two ambulances and a paramedic officer were sent to the scene after the service was alerted at 10.04am.
A spokesperson said: “On arrival crews found two men, both drivers of each car.
“The first of whom was treated for serious injuries and conveyed to the Queen Elizabeth Hospital Birmingham under blue light emergency conditions.
“The second man was treated for potentially serious injuries and conveyed to Russells Hall Hospital.”