Menstruation is black blood, consider that it may be bruised blood, because the blood stays in the uterine cavity or vagina for a long time, so the color is black. You need to see a doctor to find the cause. If it is considered to be bruising, you can use medication to nourish and invigorate the blood under the guidance of a doctor, such as choosing Angelica Pills or Easy Pills. If the menstrual flow is low, the dark color is normal, mostly seen on the first and last day of menstruation. If the entire period is dark, you need to regulate your diet, do not eat cold, cold, spicy food, you can apply heat to the abdomen, or drink brown sugar and ginger water to help improve the symptoms. If the effect is not good, you can also use warming pills under the guidance of a doctor, considering the symptoms belong to the cold in the uterus.