The emergency contraceptive pill, whose main ingredient is levonorgestrel tablets, is a remedy for contraceptive failure, or after unprotected sex, and is effective when taken within seventy-two hours. It is only effective once and only for sex within the seventy-two hours prior to taking the pill. It should not be used twice a month or more than three times a year. The emergency contraceptive pill contains a large amount of hormones, eight times the dose of the regular short-acting contraceptive pill, and is not used as a regular method of contraception, with a large number of side effects. Adverse drug reactions, including nausea, vomiting, headache, breast tenderness, irregular vaginal bleeding, and withdrawal bleeding. Emergency contraceptive pills can be absorbed and produce therapeutic effects after half an hour of taking the pill, avoiding indiscriminate use leading to menstrual disorders, amenorrhea, infertility, etc.