Six fire engines and around 40 firefighters tackled a fire at a block of flats on Hammersley Road in Canning Town.
Part of a third floor flat was damaged by the fire. One woman left the building before the Brigade arrived and was taken to hospital by London Ambulance Service.
The Brigade was called at 0446 and the incident was over for firefighters at 0636. Crews from Plaistow, East Ham, Poplar and surrounding fire stations attended the scene.
The cause of the fire is under investigation.