Five fire engines and around 35 firefighters were called to a flat fire on Dames Road, Forest Gate.
Part of a one bedroom flat on the second floor was damaged by fire. The fire also affected the roof and led to it partially collapsing onto the second floor.
Two women left the property before the Brigade arrived. One of the women was suffering from smoke inhalation and taken to hospital by London Ambulance Service crews. Ten people self evacuated from an adjacent building.
The Brigade was called at 2254 and the fire was under control at 0127. Fire crews from Stratford, Leyton, East Ham, Ilford, and Kentish Town fire stations attended the scene.
The cause of the fire is under investigation.