ChEBI: Megestrol acetate is a steroid ester resulting from the formal condensation of the hydroxy group of megestrol with the carboxy group of acetic acid. It is an appetite stimulant used for the treatment of anorexia and cachexia. Also used for birth control and for the treatment of breast cancer. It has a role as an antineoplastic agent, an appetite enhancer, a contraceptive drug, a progestin and a synthetic oral contraceptive. It is a steroid ester, an acetate ester, a 20-oxo steroid and a 3-oxo-Delta(4) steroid. It is functionally related to a megestrol. A steroid ester resulting from the formal condensation of the hydroxy group of megestrol with the carboxy group of acetic acid. It is an appetite stimulant used for the treatment of anorexia and cachexia. Also used for birth control and for the treatment of breast cancer.