The present invention is related to a dosage regimen of a steroid sulfatase inhibitor, E2MATE, for use in the prevention or treatment of endometriosis. The present invention further relates to a method for preventing or treating endometriosis.本發明關於用於預防或治療子宮內膜異位症之類固醇硫酸酯酶抑制劑(E2MATE)的給藥法。本發明另關於用於預防或治療子宮內膜異位症之方法。