Four fire engines and around 25 firefighters responded to a fire on Marsala Road, Lewisham.
The fire occurred in a mid-terraced house of two floors. Part of the buildings ground floor was damaged in the blaze. Three adults and one child were evacuated from the building by firefighters, before being assessed on scene for smoke inhalation by the London Ambulance Service, and removed to hospital.
Control Officers took the first of 14 calls reporting the fire at 0142, and crews from Lewisham, Greenwich, Lee Green and surrounding fire stations were mobilised to the scene. Firefighters were able to bring the fire under control by 0242.
The cause of the fire is under investigation by the Brigade's Fire Investigation Team.