Three crews and one officer attended.
The crews were from High Wycombe, Beaconsfield and Amersham.
A fire was located within a bedroom in a residential building.
The firefighters used four sets of breathing apparatus, two hose reel jets and immediate emergency care packs.
Four people were out on arrival and passed into the care of South Central Ambulance Service.
They also reinspected the property to check for hotspots.