Emergency contraceptive pills are generally composed of levonorgestrel, side effects disappear time, related to the specific side effects, may need 2-3 months. 1. Digestive tract reactions: such as nausea and vomiting, emergency contraceptive pills contain a large number of hormones, which can easily lead to adverse stimulation of the gastrointestinal tract, usually 2-3 days can be relieved, and even digestion. 2. Irregular vaginal bleeding: the hormones in the emergency contraceptive pill will cause the endometrium and the ovarian corpus luteum to produce a relevant reaction, which in turn induces irregular vaginal bleeding, usually lasting 3-7 days. 3. Irregular menstruation: Emergency contraceptive pills may not only cause menstrual disorders, but also delayed menstruation and early menstruation, and the recovery from this side effect will take a longer time, possibly 2-3 months. Patients with lower reproductive tract infections, pelvic inflammatory disease, and acute liver disease should not take levonorgestrel, and levonorgestrel should not be overdosed. In addition, there are certain risks associated with the administration of levonorgestrel, and patients need to be supervised by a specialist.