Taking the emergency contraceptive pill can be harmful to your body. The mechanism of emergency contraceptive pills is to prevent ovulation of the ovaries and to cause abnormal thickening of the endometrium. Because emergency contraceptive pills are highly effective progestin, the harm to the body is to break the natural ovulation pattern of the ovaries, which may cause menstrual disorders or changes in the menstrual cycle and menstrual volume, causing abnormal thickening of the endometrium. After stopping the drug, endometrial withdrawal bleeding will occur, which usually clears up on its own in 3-5 days. Therefore, it is not recommended to take the emergency contraceptive pill unless it is a last resort. It is best to use condoms or IUDs to prevent pregnancy, which are effective and safe, and cause very little harm to the body.