Capsaicin

MF&MW:C18H27NO3,305.41

Capsicum powder is an irritant for mammals, including humans, and produces a sensation of burning in any tissue with which it comes into contact;
Capsaicin powder and several related compounds are called capsaicinoids and are produced as a secondary metabolite by chili peppers, probably as deterrents against certain herbivores and fungi.Pure capsaicin is a hydrophobic, colorless, odorless, crystalline to waxy compound.