One appliance and crew from Beaconsfield and one from High Wycombe attended, along with an officer.
One of the vehicles had rolled onto its side. Three women and one man were released, injured, before they arrived. One man, one woman and two children were treated for minor injuries.
The firefighters provided assistance to South Central Ambulance Service. They made the scene safe, and used an environmental grab pack to contain a small spill on the road.
The incident was left in the hands of Thames Valley Police.