Four fire engines and around 25 firefighters were called to a fire in a building used as a suspected cannabis factory on Amhurst Road in Hackney.
Part of a ground floor hallway was damaged by fire. Firefighters wearing breathing apparatus rescued a man and a woman via an internal staircase. The man was suffering from smoke inhalation and treated by London Ambulance Service crews.
A London Fire Brigade spokesperson said:
"Cannabis factory fires can be very severe 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 booby 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 1619 and the fire was under control at 1710. Fire crews from Homerton and Stoke Newington fire station attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.