Four fire engines and 21 firefighters and officers were called to a fire at a house converted into flat on Birkbeck Road, Leytonstone.
Part of a flat on the ground floor of the building was damaged by fire. One man and one woman left before the arrival of the Brigade and were treated at the scene by London Ambulance Service. One man, one woman and two children were led to safety by firefighters wearing breathing apparatus.
The Brigade was called at 0311 and the fire was under control at 0533. Fire crews from Leytonstone and Leyton fire stations attended the incident.
The cause of the fire is under investigation.