Zoladex contains a medicine called goserelin. This belongs to a group of medicines called ‘LHRH analogues’. In men, Zoladex is used to treat prostate cancer. It works by reducing the amount of ‘testosterone’ (a hormone) that is produced by your body. In women, Zoladex is used to: Treat breast cancer. Treat a condition called ‘endometriosis’. This is where cells normally only found in the lining of the womb (uterus) are found elsewhere in your body (normally on other structures near the womb). Treat benign growths in the womb called ‘uterine fibroids’. Make the lining of the womb thinner before you have an operation on your womb. Help treat infertility (together with other medicines). It helps to control the release of eggs from the ovaries. In women, Zoladex works by reducing the amount of ‘oestrogen’ (a hormone) that is produced by your body.