Diethylstilbestrol monobenzyl ether (brand names Monozol, Hypantin, Pituitrope), also known as benzelstilbestrol, is a synthetic, nonsteroidal estrogen of the stilbestrol group and an ether of diethylstilbestrol (DES) that is described as a pituitary gland inhibitor (antigonadotropin) and was formerly marketed but is now no longer available.[1] [2] It was first synthesized by Wallace & Tiernan Company in 1952, and was described by them as having only weak estrogenic activity.[3] The drug was used to treat gynecological conditions and infertility in women.