Four fire engines and around 25 firefighters were called to a fire at a house on Krithia Road in Dagenham.
Most of the first floor was destroyed by fire. Two adults and five children left the property before the Brigade arrived. One woman was treated on scene by London Ambulance Service.
The cause of the fire is accidental and is believed to be caused by a hairdryer.
A London Fire Brigade spokesperson said: "This is a good opportunity to remind people how important it is to ensure that hairdryers and straighteners are turned off at the plug as well as on the appliance.
“Firefighters also recommend that you have a look at our online Home Fire Safety Checker to make sure there are no hidden hazards in your home.
“The online tool will ask you a series of questions that will help us work out the level of risk in your home, or the home of someone you care for. It only takes a few minutes to get tailored advice to keep yourself and loved ones safe from fire.”
The Brigade was called at 1823 and the incident was over by 1925. Fire crews from Barking and East Ham fire stations were at the scene.