Two fire engines and around 10 firefighters were called to a fire at a shop on Tooting High Street in Tooting.
A fire in a stock cage used to store rubbish was discovered by an employee who called the Brigade. Four people were treated at the scene for smoke inhalation by London Ambulance Service crews but were not taken to hospital.
The Brigade was called at 2115 and the fire was under control by 2213. Fire crews from Wimbledon and Tooting fire stations attended the scene.
The cause of the fire is under investigation.