The side effects of the morning-after emergency contraceptive pill are often the following in clinical practice: 1. Gastrointestinal reactions, nausea, vomiting or dizziness may occur, the vast majority of patients will disappear naturally the next day and the reactions are mild. 2. Since the emergency contraceptive pill is a highly effective progestogen, it will lead to abnormal thickening of the endometrium after it is taken in clinical practice, so it is possible that after stopping the pill there will be Retreating bleeding. The withdrawal bleeding usually lasts about 3-5 days and the amount is relatively small. 3. Because the emergency contraceptive pill can not only inhibit the natural ovulation of the ovaries, but also cause endocrine disorders and menstrual disorders in clinical practice. 4. Liver and kidney function damage may occur in relatively sensitive people.