One crew from Gerrards Cross, one from Hillingdon and one from Langley attended, along with two officers.
One man was out of his car when they arrived. One woman released herself from her car and was passed into the care of South Central Ambulance Service.
The firefighters provided immediate emergency care and made the scene safe.
Two lanes of the motorway were closed while the emergency services worked at the scene.
National Highways also attended.