capsaicin cap·sa·i·cin (kāp-sā'ĭ-sĭn)
A colorless, pungent, crystalline compound that is derived from the capsicum pepper and is a strong irritant to skin and mucous membranes.
A colorless, extremely pungent, crystalline compound that is the primary active principle producing the heat of red peppers. It is a strong irritant to skin and mucous membranes and is used in medicine as a topical analgesic. Capsaicin is highly stable, retaining its potency for long periods and despite cooking or freezing. Chemical formula: C18H27NO3.