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. Pure capsaicin is a volatile, Hydrophobic, colorless, odorless, crystalline to waxy compound. Because of the burning sensation caused by capsaicin when it comes in contact with mucous membranes, it is commonly used in food products to give them added spice or "heat". In high concentrations, capsaicin will also cause a burning effect on other sensitive areas of skin. The degree o...