The emergency contraceptive pill works on the second day of intercourse, because the specific method of taking the emergency contraceptive pill, which is taken orally within 72h after intercourse, will inhibit ovulation and cause abnormal thickening of the endometrium to prevent fertilization of the egg, so the purpose of contraception is achieved. For emergency contraceptive pills, it is recommended to take them at most twice a year, but not often, because the side effects of this drug are still relatively large. Because it inhibits the natural ovulation pattern of the ovaries, it may lead to endocrine disruption and menstrual disorders. In addition, it can also cause abnormal thickening of the endometrium, which can lead to withdrawal bleeding and increase inflammatory reactions, so it is recommended to use condoms or intrauterine devices for contraception in daily life.