In general, menstruation lasts 2~8 days, so there is still a small amount of blood on the fourth and fifth day of menstruation, which is usually normal if it is not accompanied by other uncomfortable symptoms. A woman’s menstruation is produced by the shedding of the uterine lining, which normally lasts 2~8 days, with a bleeding volume of 20~60ml, and the pattern of the bleeding shows that it varies from less to more and then becomes less. If there is still a small amount of blood on the fourth or fifth day of menstruation, this is generally normal, but if there is significant dysmenorrhea and a small amount of blood after the eighth day of menstruation, this is abnormal. If a woman’s menstruation shows obvious changes, excessive bleeding or lasts too long, she needs to go to the hospital in time, and under the guidance of the doctor to carry out standardized treatment, to promote the alleviation of the condition.