Emergency contraceptive pills cannot be taken twice in a month. Emergency contraceptive pills must be taken within 72 hours of sexual intercourse and are composed of high doses of hormones, so they should not be taken more than once a month. Taking too many pills in a short period of time will cause disruption of the menstrual cycle, affect ovarian function, and in severe cases, may also lead to infertility. Emergency contraceptive pills refer to contraceptive measures taken after sexual intercourse to avoid unwanted pregnancy. Emergency contraceptive pills can only be used as a back-up method to prevent pregnancy, and cannot be used as a regular contraceptive measure. Patients taking emergency contraceptive pills may experience side effects such as delayed menstruation, early menstruation, increased menstrual flow, nausea, vomiting and epigastric discomfort. It is recommended that patients who need to use emergency contraceptive pills should go to the hospital for consultation and take the pills as prescribed by the doctor to avoid side effects.