Three fire engines and around 15 firefighters tackled a flat fire on Anne Street, Plaistow.
Part of a first-floor flat was damaged by the fire. A man and a woman were rescued from the flat by firefighters using breathing apparatus, and were treated on scene by London Ambulance Service crews. The woman was taken to hospital for further treatment. Firefighters also rescued a cat from the property.
The fire is believed to have been accidental and caused by an unattended candle.
A London Fire Brigade spokesperson said: “Candles are one of the most common causes of fire. It’s really important that you never leave a candle unattended and keep them away from anything else that can easily catch fire.”
The Brigade was called at 2138, and the fire was under control by 2248. Fire crews from Plaistow, Stratford and East Ham fire stations attended the scene.