Six fire engines and 35 firefighters and officers were called to a fire at a house in Burnham Road, Chingford.
The first floor of the semi-detached house was gutted by the blaze. Part of the ground floor was also damaged by fire.
Two men left the property before the arrival of the Brigade. Both men were treated at the scene for smoke inhalation by London Ambulance Service crews before being taken to hospital.
The Brigade was called at 1206 and the fire was under control at 1344. Fire crews from Walthamstow, Woodford, Edmonton and Tottenham fire stations attended the scene.
The cause of the fire is under investigation.