If the patient’s menstruation is usually very regular, and after taking the contraceptive pill, the menstruation has advanced by half a month, it is mainly suggestive of the following three possibilities: first, withdrawal bleeding after taking emergency contraceptive pills. Because the emergency contraceptive pill is a highly effective progestin, it is easy to disrupt the female endocrine after taking the pill. When the metabolism of the pill ends, the hormone level drops, there will be a sudden drop in the hormone level, the endometrium loses the support of the hormone level, resulting in exfoliative bleeding. This kind of bleeding is usually very small, and will be clean within 3-4 days, and does not need special treatment. Secondly, it is important to consider that ovulation bleeding has nothing to do with taking birth control pills. Ovulation bleeding usually occurs in the middle of menstruation, and is related to the transient decrease of estrogen during ovulation, and does not need to be treated once in a while. Thirdly, we should consider the menstrual disorders caused by taking contraceptive pills. In this case, the treatment plan should be chosen according to the amount and duration of bleeding. If it can be stopped within a short period of time and the bleeding is very small, it does not need to be treated. If there is a lot of bleeding, it is necessary to use drugs to stop bleeding, such as Yunnan Baiyao and Gongxunin, for treatment.