Three fire engines and around 15 firefighters were called to a fire at a flat on Quilters Place in Eltham.
A small part of a kitchen in a ground floor flat was damaged by fire. Firefighters wearing breathing apparatus led one woman to safety who was treated on scene after suffering from smoke inhalation.
The Brigade’s Fire Investigators believe the fire was accidental and involved a toaster.
A London Fire Brigade spokesperson said: “It’s really important that you always check toasters and other appliances are turned off and unplugged when not in use, unless they’re designed to be left on- like your fridge or freezer.
"Keep clutter to a minimum on your kitchen work surfaces especially near toasters and hobs as they can accidentally switch them on or catch fire."
The Brigade was called at 0903 and the fire was under control by 0927. Fire crews from Eltham and Sidcup fire stations attended the scene.