Diethylstilbestrol (DES), also known as stilbestrol or stilboestrol, is a nonsteroidal estrogen medication, which is rarely used. In the past, it was widely used for a variety of indications, including pregnancy support for women with a history of recurrent miscarriage, hormone therapy for menopausal symptoms and estrogen deficiency in women, treatment of prostate cancer in men and breast cancer in women, and other uses. [Source: Wikipedia ]