Four fire engines and around 25 firefighters tackled a house fire on Swaton Road in Bow.
Half of the first floor of the two-storey terraced house was damaged by fire.
Three people left the property before firefighters arrived. They were treated by London Ambulance Service crews for smoke inhalation.
The Brigade was called at 0317 and the fire was under control by 0421. Firefighters from Poplar, Millwall, Stratford and Bethnal Green fire stations attended the scene.
The cause of the fire is under investigation.