Hexestrol (INN) (brand name Synestrol, Synoestrol, Estrifar, Estronal, numerous others), also known as hexanestrol, hexoestrol, and dihydrodiethylstilbestrol, is a synthetic, non-steroidalestrogen of the stilbestrol group related to diethylstilbestrol that was used to treat estrogen deficiency but is now no longer employed medically.