One fire engine and crew from Buckingham and one from Bicester attended, along with an officer.
One car had overturned and was on its roof, following a collision between two cars.
Firefighters used hydraulic rescue equipment and small tools to release one man, injured, who was passed into the care of South Central Ambulance Service.
A second man, and a woman, were both out of their cars, uninjured, before the firefighters arrived.
Thames Valley Police also attended.
The road was closed while the emergency services worked at the scene.