Emergency contraceptive pills are usually taken orally within 72 hours after intercourse, the sooner the better, on an empty stomach. Emergency contraceptive pills generally contain a large number of progesterone components, it is recommended that women who do not have a plan to get pregnant and need emergency contraception, should be taken within 72 hours after intercourse. It is also recommended to take the pill on an empty stomach, that is, do not eat for two hours before and after taking the pill to avoid nausea and vomiting and other adverse reactions. If you vomit after taking the pill, you should take a refill as soon as possible after vomiting out the drug to avoid contraceptive failure. In addition, if you want to take the emergency contraceptive pill, you must take it as soon as possible, the sooner you take it, the better the effect. Taking emergency contraceptive pills may also cause women to experience menstrual disorders, abnormal vaginal bleeding and other adverse reactions, as well as occasional nausea and vomiting, headache and dizziness, breast swelling and pain, fatigue and weakness. Emergency contraceptive pills are contraindicated in women over 40 years old, in patients with breast cancer, reproductive organ cancer and other tumors, in patients with mental depression, and in those with severe liver insufficiency. Patients with serious chronic diseases such as hypertension, cardiovascular and cerebrovascular diseases, diabetes, hyperlipidemia and other patients should not take it. However, pregnant women should also note that the pill is not 100% contraceptive, if there is a delay in menstruation, we should seek medical advice as soon as possible to find out whether there is a possibility of unwanted pregnancy.