​​​​​​What makes Hot Peppers Hot?

It is an irritant for Mammals, including Humans, and produces a sensation of burning in any tissue with which it comes into contact. Capsaicin and several related compounds are called capsaicinoids and are produced as secondary metabolites by chili peppers, probably as deterrents against certain mammals and fungi. Capsaichin is the chemical in Chili Peppers that makes them spicy. Specifically, capsaichin occurs in the fruits of plants in the Capsicum family, including bell peppers, jalapeño peppers, cayenne peppers and other chili peppers. The seeds of the peppers don't contain any capsaichin at all.