Because carbon monoxide (CO) is a colorless and odorless gas, symptoms of CO poisoning are difficult to recognize, making CO a hidden killer in home environments. To prevent CO poisoning, we used artificial intelligence and Internet of Things (IoT) technology to develop a CO poisoning prevention system with the following functional features: (1) a CO sensor, which was installed in the bathroom at home and immediately activated to warn the household when the CO concentration was excessively high; (2) an electric window opener and a fan, which when activated performed forced ventilation and thereby reduced CO concentration; (3) a device that cut off the gas supply; (4) a Line application that notified family members and signaled the community management center to conduct emergency rescue operations; and (5) a mechanism for unlocking the door to allow people to enter for emergency rescue. The obtained results may help reduce the number of CO poisoning cases and casualties in the winter in Taiwan.