Two appliances and crews from Aylesbury and two officers attended.
One man and one woman were out of the house when they arrived. A second woman was in the care of South Central Ambulance Service. A dog, believed to be suffering the effects of carbon monoxide poisoning, was released from the building and the firefighters used two sets of breathing apparatus and a gas monitor.
They isolated the gas supply, ventilated the house, and provided advice.
The gas provider also attended.