Bufothionine is a sulfur-containing compound which is present in the bufotoxins secreted by the parotoid gland of certain toads of the genera Bufo and Chaunus. This specific compound can be found in the skin of certain species of toad such as the Asiatic Toad, Chaunus arunco, Chaunus crucifer, Chaunus spinulosus, and Chaunus arenarum.