Emergency contraceptive pills are usually taken on an empty stomach for two hours, that is, two hours before taking the pill and two hours after taking the pill can not eat or drink. Emergency contraceptive pill is a kind of after-the-fact remedial medicine, the dose of progesterone is very large, more side effects, may affect the menstrual cycle, affect ovulation, and even affect the ovarian function, can not be used more than three times a year, can not be used as a regular contraceptive to contraceptives, so take the pill after each sexual life should be strictly extra with condoms throughout the contraception, there is no 100% contraceptive effect. It is recommended to use short-acting oral contraceptives to contraceptives, such as Yusmin, Yusiyue, Daying-35, this contraceptive pill contraceptive effect is very good, and the side effects are very small.