Four fire engines and around 25 firefighters tackled a fire at a flat on Breamore Road in Goodmayes.
Half of a flat on the ground floor of a three-storey building was damaged by fire.
One woman was rescued by firefighters wearing breathing apparatus from the ground floor and taken to hospital by London Ambulance Service crews. Firefighters wearing breathing apparatus used fire escape hoods to rescue three adults from neighbouring flats. They were assessed at the scene by ambulance crews.
Two adults and two children were led to safety from a flat by a member of the public before firefighters arrived. They were all taken to hospital by ambulance crews suffering from smoke inhalation.
A further adult was treated by ambulance crews.
Fire escape hoods provide members of the public with up to 15 minutes protection from four of the main fire gases (carbon monoxide, hydrogen cyanide, hydrogen chloride and acrolein) and can be worn by conscious or unconscious people. If more than 15 minutes protection is required then another hood can be given to each wearer. They do not provide oxygen but temporarily filter toxic smoke to make breathing easier.
Road closures were put in place to allow emergency services to work safely.
The Brigade was called at 1025 and the fire was under control by 1208. Crews from Ilford and Dagenham fire stations attended the scene.
The cause of the fire is under investigation.