An elderly woman was rescued from her flat when it caught fire.
It happened in Etloe Close, Leyton, at around 8.45pm on Tuesday.
Fire-fighters helped her from the property and gave her oxygen. She was then taken to hospital by ambulance and treated for smoke inhalation.
A small part of her flat was damaged.
A spokesman for the London Fire Brigade said: "The fire is believed to have been caused by a tea towel left on an electric hob."
Watch Manager Rod Wainwright, from Leyton fire station, who attended the scene, said: “Never leave anything that could catch fire on top of your hob, even when it’s switched off.
"Hobs can be accidentally left on, or can be turned on by mistake – so it’s best to keep it clear at all times.
"Make sure you have a working smoke alarm too, as it will alert you to a fire very quickly, giving you time to escape your home without getting hurt.”
Two fire engines from Leyton fire station attended and brought the fire under control at just after 9pm.