()-Enterodiol-13C3 is the 13C-labeled ()-Enterodiol (HY-108695B). ()-Enterodiol is the racemate of Enterodiol (HY-108695). Enterodiol is transformed by human intestinal bacteria from lignans contained in various whole-grain cereals, nuts, legumes, flaxseed, and vegetables. Enterodiol has an apoptotic effect in colorectal cancer (CRC) cells. Enterodiol has anti-cancer activities[1][2].