Emergency crews were called to a two-car crash on the A20 at West Kingsdown, near Brands Hatch.
Four people were treated at the scene and two from one vehicle were taken to hospital. The extent of their injuries is not yet known.
It was initially thought that people could be trapped as one of the cars had overturned in the crash on London Road at about 11.30pm last night.
The road was closed both ways while the vehicles were recovered.
Firefighters from Dartford and Larkfield helped to make the road safe.