The emergency contraceptive pill is a remedial drug, which contains a large dose of progestin, equivalent to the dose of progestin in the 8-day short-acting oral contraceptive pill, mainly through delaying ovulation or suppressing ovulation to achieve the remedial effect, so it should not be taken more than 3 times a year, which may have certain effects on women’s menstrual cycle and hormone levels, and may also cause damage to liver function and Gastrointestinal disorders. It is better to use the short-acting oral contraceptive pill to prevent pregnancy, the dose of progestin in the short-acting oral contraceptive pill is relatively small and safe, generally a box is a 21-day dose, take one tablet every day, can not miss, stop 7 days, the eighth day to take the second box. The remedial effect of the emergency contraceptive pill is about 85%, and the probability is not great. It is best to switch to the short-acting oral contraceptive pill as one of the regular contraceptives.