Kent Fire and Rescue Service responded to a fire in an outbuilding on Regent Street in Rolvenden near Tenterden in the early hours of Tuesday morning.
Four fire engines arrived at the scene, and crews wearing breathing apparatus used high-pressure hose reel jets to extinguish the flames.
One casualty was treated for smoke inhalation by firefighters before being transferred to the care of South East Coast Ambulance Service paramedics. The fire is believed to have been accidental and linked to a washing machine.