The common reasons for the dark color of menstrual blood include: 1, the black color of menstrual blood caused by the patient’s previous multiple abortions or cleanings, resulting in cervical adhesions, cervical adhesions, and poor discharge of menstrual blood; 2, due to eating food frozen in the refrigerator, using cold water to wash hands, face, feet, or staying in a too cold environment for a long time before or during the menstrual period. The contraction of the uterus and the discharge of menstrual blood are affected by staying for a long time; 3. Suffering from more serious gynecological inflammatory diseases such as endometritis, pelvic inflammatory disease and cervicitis can also affect the normal flow of menstrual blood and lead to black menstrual blood. The specific causes vary among different patients and need to be analyzed and determined according to the actual situation.