A stink bomb is a device designed to create an unpleasant smell. They range in effectiveness from simple pranks to military grade malodorants or riot control chemical agents.

The Guinness Book of Records lists two smelliest substances. One is "US Government Standard Bathroom Malodor"; a mixture of eight chemicals with a stench resembling human feces, only much stronger, designed to test the efficacy of deodorizers and air fresheners. Another one, "Who me?", is a mixture of five sulfur-containing chemicals and smells like rotting food and carcasses.

Range

At one end of the spectrum, relatively harmless stink bombs consist of ammonium sulfide, which smells strongly of rotten eggs. When exposed to air, the ammonium sulfide reacts with moisture, hydrolyzes, and a mixture of hydrogen sulfide (rotten egg smell) and ammonia is released. Other popular substances on which to base stink bombs are thiols with lower molecular weight, e.g., methyl mercaptan and ethyl mercaptan—the chemicals that give odor to skunks and are added in minute quantities to natural gas in order to make gas leaks detectable by smell. A variation on this idea is the scent bomb, or perfume bomb, filled with an overpowering "cheap perfume" smell.