Symptoms similar to early pregnancy reaction such as nausea and vomiting after taking emergency contraceptive pills will disappear in 2-3 days after stopping the pills. The side effects of emergency contraceptive pills are mainly nausea, vomiting and breast swelling, which will disappear slowly after stopping the pills. The common side effect is nausea, and vomiting is less common. If the symptoms of vomiting are more serious after taking the pill, you need to take additional birth control pills, which can reduce the symptoms. There are other side effects of emergency contraceptive pills, withdrawal bleeding will occur within 7 days after taking the pill, but if you take it after ovulation, withdrawal bleeding will not occur, which will lead to delayed menstruation, and some people may also experience vaginal bleeding, but do not worry, menstruation will return to normal in 1-2 months after stopping the pill.