Canthaxanthin is a naturally occurring carotenoid pigment found in various plants, mushrooms, and marine organisms. It is commonly used as a coloring agent in animal feed, cosmetics, and food industry. The pigment has several synonyms that include E161g, Roxanthin Red 10, 4,4'-Diapocarotenoic acid, beta,beta'-carotene-4,4'-dione, and trans-Canthaxanthin. E161g is a standardized designation for canthaxanthin that is approved by the European Union. Roxanthin Red 10 is a commercial name for the pigment that is used in the poultry industry. 4,4'-Diapocarotenoic acid and beta,beta'-carotene-4,4'-dione are chemical names that describe the molecular structure of canthaxanthin.