The third day of menstruation is black, considering that the amount of menstruation is too small or not discharged smoothly, and related to cold, endocrine disorders and other factors, the treatment needs to be based on the cause of the disease through the general treatment, medication and other ways of active treatment. 1. Cold: If a woman craves for cold and drinks cold during menstruation, and wears too thin clothes, it will easily lead to cold in the abdomen, which in turn affects the stripping of the endometrium, leading to the inability of the menstrual blood to be discharged normally, and the dark color of the menstrual period, abdominal pain and other discomforts, at this time, you can drink brown sugar and ginger water, or use heating pads, hot-water bags, etc. to warm up the abdomen. 2. Endocrine disorders: (1) mental stress: if the patient recently work pressure is relatively large or often stay up late, it may cause endocrine disorders, which in turn cause irregular ovulation or non-ovulation of the ovaries, and menstruation dark color, prolonged menstrual period and other discomforts, at this time, women should be appropriate relaxation, adjusting the lifestyle, and if necessary, can be used in accordance with the doctor’s orders to adjust the menstrual cycle of progesterone preparations. (2) Gynecological endocrine diseases: For women with polycystic ovary syndrome, premature ovarian failure and other gynecological endocrine diseases, due to the irregular discharge of follicles, which affects the stripping of the uterine lining and the appearance of dark menstrual cycle, at this time, you can follow the doctor’s advice to take progestin, short-acting contraceptives, estrogen and other hormonal preparations to adjust the menstrual cycle. For women whose blood is black on the third day of menstruation, it is recommended that they go to the gynecology department of a regular hospital, complete the ultrasound, sex hormones and other relevant examinations, and then take active treatment under the guidance of the doctor after clarifying the cause of the disease.