Under normal circumstances, it is normal to have a period within 3-7 days. If there is still brown color on the 6th day of menstruation, it is okay, if the brown blood is completely clean within 7 days, it is all normal. Therefore, it does not matter if there is still brown on the 6th day of menstruation, the brown color indicates that it is almost cleared. If the period is not clean for more than 7 days, it indicates that there is an abnormality, commonly endometrial polyps, which can occur only after 8 or 9 days of menstruation. The presence of polyps can be determined by the thickness of the endometrium and the presence of polyps can be determined by the echo of the endometrium. Therefore, if there is blood after 7 days of menstruation, you must do the corresponding examination. Ultrasound can determine whether there are endometrial polyps or submucosal fibroids. The presence of polyps and submucosal fibroids can cause the period to be more than 7 days old and the cycle to be particularly short. Therefore, it does not matter if there is still brown blood on the 6th day of menstruation, do not worry, if the blood is completely clean on the 7th day, it is normal and not a big problem.