Four fire engines and around 25 firefighters were called to a fire at a house being used as a suspected cannabis factory on Station Terrace in Queen's Park.
Part of the ground floor hallway was damaged by the fire. One woman was treated on scene by London Ambulance Service crews. Two cats were rescued by firefighters wearing breathing apparatus via a ladder.
A London Fire Brigade spokesperson said: “Cannabis factory fires can be particularly dangerous because of the way criminals use unsafe wiring to illegally obtain electricity in order to grow the plants.
"They're often in top floors or lofts which means when a fire takes hold it spreads, destroying roofs and damaging neighbouring buildings.
"Firefighters can also be exposed to risks when dealing with the fires because of bad wiring and traps at some of the properties.
"It's important that people know the key signs and inform the police so that they can act swiftly to prevent these dangerous fires from happening."
The Brigade was called at 2028 and the fire was under control by 2330. Firefighters from Willesden, North Kensington, Paddington and West Hampstead fire stations attended the scene.
The cause of the fire is under investigation.