Mifepristone is an antagonist of progesterone, and it has three main uses in clinical practice: first, medication abortion, because it can antagonize progesterone, so after pregnancy patients taking mifepristone, the effect of progesterone will decrease, so patients will experience embryonic death. It is usually required that the patient is pregnant within 49 days and can choose a medication abortion, which requires a combination of mifepristone and misoprostol to do so. Second, it is mainly used for contraception, mostly for emergency contraception. Patients are required to have unprotected sex and take it within 120 hours. The earlier the better, generally take one piece can be, the contraceptive effect is very good, the chance of unintended pregnancy in about 2%-4%. Third, it can be used to regulate menstruation and can be used as artificial amenorrhea.