Megestrol tablets are used to relieve the symptoms and reduce the suffering caused by advanced breast cancer and advanced endometrial cancer (cancer that begins in the lining of the uterus). Megestrol suspension is used to treat loss of appetite, malnutrition, and severe weight loss in patients with acquired immunodeficiency syndrome (AIDS). Megestrol should not be used to prevent loss of appetite and severe weight loss in patients who have not yet developed this condition. Megestrol is a man-made version of the human hormone progesterone.