Eight fire engines and around 60 firefighters were called to a fire at a flat in Victoria Road, Plaistow.
Around half of a third floor flat was damaged by fire. Fifteen people left the building before the arrival of the Brigade. Firefighters led one woman to safety via the internal staircase. She was treated at the scene for smoke inhalation and shock before being taken to hospital by London Ambulance Service crews.
The Brigade was called at 0207 and the fire was under control at 0315. Fire crews from Statford, Leytonstone, Leyton, Millwall, Barking, Plaistow, Poplar, and East Ham fire stations attended the scene.
The cause of the fire is under investigation.