I know how you feel, you want to be able to breath fire, but you are not too keen on putting poisonous chemicals in your mouth. In this Instructable, I'll show you how to blow a 10-foot-high plume of fire out of your mouth. Obviously any activity that involves large quantities of fire has some risk, but this method of firebreathing uses foods as fuel, so there is no danger of poisoning from ingestion of the fuel. Also the fuel is not flamable unless it is aerosolized. This means that if you spill on yourself, your shirt is probably no more likely to catch fire than it was before. With that said, I take no responsibility for your safety.
The companion video provides instuctions and a demonstration.