Firefighters were called to a house fire in Stonald Road in Whittlesey on Friday night.
All the occupants of the house were accounted for before crews arrived but two people were given oxygen therapy before being taken to hospital with smoke inhalation as a precaution.
Crews from Whittlesey and Stanground attended the fire which shut the road for some hours.
Firefighters using breathing apparatus used a hose reel and covering jet to extinguish the fire and a positive pressure ventilation fan to clear the smoke.Station Commander Jamie Johnson said the fire was caused by candles which had been left unattended in a downstairs dining room.
He added: “There were no smoke alarms in the house and the candles had been left unattended in the dining room. Some passersby saw the flames and were banging on the window to alert the people inside.
“Smoke alarms are vital to saving lives and should be installed in every home and business and tested regularly.”
Fenland Police tweeted a thank you for the quick response of the fire crews and a passer-by who raised the alarm.