At the lower end of the spectrum, relatively harmless stink bombs consist of a mixture of ammonium sulfide, vinegar and bicarbonate, 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. Another mixture consists of hydrogen sulfide and ammonia mixed together directly.
Other popular substances on which to base stink bombs are thiols with lower molecular weight such as methyl mercaptan and ethyl mercaptan—the chemicals that 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.
At the upper end of the spectrum, the governments of Israel and the United States of America are developing stink bombs for use by their law enforcement agencies and militaries as riot control and area denial weapons. Using stink bombs for these purposes has advantages over traditional riot control agents: unlike pepper spray and tear gas, stink bombs are believed not to be dangerous, although their psychological effects can make people sick.
Prank stink bombs and perfume bombs are usually sold as a 1- or 2-mL sealed glass ampoule, which can be broken by throwing against a hard surface or by crushing under one's shoe sole, thus releasing the malodorous liquid contained therein. Another variety of prank stink bomb comprises two bags, one smaller and inside the other. The inner one contains a liquid and the outer one a powder. When the inner one is ruptured by squeezing it, the liquid reacts with the powder, producing hydrogen sulfide, which expands and bursts the outer bag, releasing an unpleasant odor.