Four fire engines and around 25 firefighters were called to a fire at a flat in Sterry Road, Dagenham.
Half of a ground floor flat was damaged by fire.
A man left the property before the Brigade arrived and was treated at the scene by London Ambulance Service crews.
The Brigade was called at 1213 and the fire was under control by 1251. Fire crews from Dagenham, Ilford, Barking and East Ham attended the scene.
The cause of the fire is under investigation by London Fire Brigade and the Metropolitan Police.