Four fire engines and around 25 firefighters were called to a fire at a pub on Albert Road in North Woolwich.
Half of the first floor was damaged by the blaze. Five people left the property before the Brigade arrived. One woman was taken to hospital by London Ambulance Service crews.
The Brigade was called at 0734 and the fire was under control by 0845. Fire crews from Plaistow, East Ham, Barking and Dagenham fire stations attended the scene.
The cause of the fire is under investigation.