Normally, menstrual blood is dark red, and it does not clot. There are also people who have relatively small clots that are normal, but having large clots is not normal. The light color of menstrual blood is often clinically caused by the following reasons: first, inflammation of the endometrium, which can lead to a large amount of local exudation and dilution of menstrual blood when menstruation occurs, and the first two days of menstruation are light in color, and often accompanied by dysmenorrhea and pain in the lower abdomen in daily life. Secondly, the patient has anemia, the red blood cells will be reduced, the blood will appear lighter in color, and the menstrual blood will also be lighter in color. It is recommended to do ultrasound examination to understand the endometrial condition, scrape the uterus if necessary, and send the scraped tissue for pathological examination, as well as routine blood test to understand whether there is anemia.