Cloxestradiol, also known as 17-(2,2,2-trichloroethoxy)estradiol, is a synthetic, steroidal estrogen which was never marketed.[1] It is an analogue of estradiol with a 2,2,2-trichloroethoxy substitution. The O,O-diacetate derivative, cloxestradiol acetate (brand name Genovul), has been marketed as an estrogen.