It is normal for a patient to bleed black after taking the pill because withdrawal bleeding occurs about 3-7 days after taking the pill. If the patient takes the pill for a longer period of time, the amount of bleeding will be significantly reduced and the color of the bleeding will be black, which is normal. Because of the side effects of the pill, women who take it for a long time or temporarily will have certain effects on endocrine secretion, and when women have their menstruation, the blood and secretions will mix and appear black. It is also possible that women take the emergency contraceptive pill just after their period, in which case the blood will also appear black in color. As you can see, there are many reasons for black blood, but if the bleeding is relatively small and short-lived, it does not need to be treated.