Different reactions occur after taking the emergency contraceptive pill and vary from person to person. First of all, common reactions include nausea, vomiting, dizziness, feeling fatigue, and swelling and pain in the breasts, etc. Symptoms are relieved after 24 hours of taking the pill and after the peak of drug metabolism. In order to reduce the gastrointestinal reactions of the emergency contraceptive pill, it is recommended to take it about 2 hours after dinner and not to eat too greasy food or stimulating food. Secondly, irregular vaginal bleeding after taking the pill may occur about 3-4 days after taking the pill, because a large amount of progesterone enters the body and affects the normal estrogen level, resulting in withdrawal bleeding from the endometrium, which is not large and lasts for about 2-3 days. After taking the emergency contraceptive pill, it is easy to cause delay of menstruation, the delay time is about 3-7 days, the longest time is not more than 10 days, otherwise, consider the possibility of contraceptive failure.