Kent Fire and Rescue Service was called to a house fire in The Street in Mereworth, near Maidstone.
Four fire engines, a height vehicle and KFRS’ Volunteer Response Team attended.
Crews wearing breathing apparatus used two main jets, two hose reel jets and water from a hydrant to tackle the blaze on the first floor, which had spread into the roof space.
One adult suffering burns, and two adults and a child suffering the effects of smoke inhalation, were outside the house on arrival and were handed into the care of SECAmb paramedics.
Firefighters managed to rescue two cats from the property. The fire is believed to have started in a bedroom on the first floor, but the cause is not yet known.