Four fire engines and 21 firefighters and officers were called to a fire at a house converted into flats in Plashet Grove in East Ham.
A ground floor flat was damaged by fire. One woman was rescued from the flat by firefighters wearing breathing apparatus and she was treated at the scene by London Ambulance Service crews before being taken to hospital.
One man left the first floor flat before the arrival of the Brigade.
The Brigade was called at 1509 and the fire was under control at 1606. Fire crews from East Ham, Stratford, Plaistow and Leytonstone fire stations attended the scene.
The cause of the fire is believed to be accidental.