Three fire engines and around 15 firefighters were called to a fire at a flat on Sandling Rise in Eltham.
Part of a four-roomed flat on the first floor was damaged by the blaze. One man left the property before the Brigade arrived. Another man from a neighbouring property tried to extinguish the fire with a garden hose. Both men were treated on scene for smoke inhalation by London Ambulance Service crews.
A London Fire Brigade spokesperson said: "A neighbour tried to extinguish this fire themselves with a garden hose.
"Our advice would always be not to tackle fires yourself and leave it to the professionals. Get out, stay out and call 999 immediately."
The Brigade was called at 1752 and the fire was under control by 1914. Fire crews from Eltham and Sidcup fire stations attended.