The emergency use of the pill is taken within 72 hours of unprotected sex. Emergency use of contraceptives generally refers to the emergency contraceptive pill, which is a kind of contraceptive measures taken after sexual intercourse, it is generally recommended to take the pill as soon as possible after sexual intercourse, generally the earlier the pill is taken, the better the contraceptive effect is, if the pill is taken more than 36 hours, the effect will be weakened, but it is generally believed that the pill is effective if it is taken within 72 hours. Emergency contraceptive pills only have a certain contraceptive effect on the current sexual intercourse, if you have sex again after taking the pills, you need to take the emergency contraceptive pills again in order to avoid unwanted pregnancy, and if you vomit after taking the emergency contraceptive pills, you need to take another pill.