There are several reasons for the dark color of women’s menstruation: 1, because of gynecological inflammation, such as vaginitis, endometritis, pelvic inflammatory disease, salpingitis, etc., especially endometritis and vaginitis. Normal menstruation is formed by the cyclic contraction and diastole of the small arteries of the endometrium. If the endometrium is inflamed, the exudate material of inflammation, as well as bacterial secretion material and metabolic wastes, can be mixed into the menstruation in the process of menstruation, thus leading to deepening of the color of menstruation. Menstruation has to flow through the vagina, if there is inflammation in the vagina, that is, vaginitis can also lead to deepening of the color of menstruation. 2, because there is stasis in the body, because the normal blood circulation in the organism is always going on, if there is stasis in a part of the body or the blood circulation is slowed down, the amount of oxygen-containing hemoglobin in the blood in this part of the body will drop, and the hemoglobin will be relatively increased, which will lead to the darkening of the color of the blood and will also lead to deepening of the color of menstruation. Deepening of menstrual color.