Firefighters were called to a suspected carbon monoxide leak at flats above a shop on Sydenham Road in Sydenham.
A woman and a child were taken to hospital after suffering from suspected carbon monoxide poisoning. Four further people from a neighbouring flat left the building and a man later went to hospital.
Firefighters used specialist equipment to carry out a systematic sweep of the building to check for elevated readings of chemical substances. Crews ensured no elevated readings remained before leaving the scene.
A London Fire Brigade spokesperson said: “You can't taste, see or smell CO fumes, but it can kill in minutes.
"It's really important to fit a CO alarm in all rooms containing fuel burning appliances, ensuring that the alarm is able to be heard throughout the property. When sleeping, it's important that your alarm can wake you if it sounds.
"It’s also a good idea to familiarise yourself with the signs of carbon monoxide poisoning and learn what to do if you suspect someone may be affected.”
The Brigade was called at 1615 and the incident was over for firefighters by 1904. Two fire engines and two fire rescue units from Forest Hill, Beckenham, Lewisham and Bethnal Green fire stations attended the scene.
These symptoms also apply to your pets – so keep an eye on them too. Poisoning symptoms can easily be confused with just feeling unwell, which is why CO poisoning is so dangerous, and so often missed.