Four fire engines and around 25 firefighters were called to a fire at shop on Wood Street, Walthamstow.
A roll of carpet at the rear of the property was destroyed by fire and part of the ground floor was damaged by fire. The fire is also damaged a small part of an adjacent shop and a residential property.
The Brigade's fire investigators believe the cause of the fire was the unsafe disposal of smoking materials which ignited combustible materials.
A London Fire Brigade spokesperson said: "We would rather people didn’t smoke at all but if they do, vaping is a safer option.
"If you do choose to smoke cigarettes, it is absolutely vital you ensure your cigarette is completely out when you’ve finished smoking it.
"If you don’t, you risk causing a fire which could not only destroy your home, but also cost you your life."
One man was treated at the scene by London Ambulance Service crews.
The Brigade was called at 1307 and the fire was under control at 1532. Fire crews from Walthamstow, Leyton, Leytonstone, and Tottenham fire stations attended the scene.