What does it mean if the first day’s menstrual blood is black?

Generally, menstrual blood is dark red in color because it often mixes with shed fragments of the endometrium, cervical mucus, and vaginal epithelial cells. Many women become alarmed upon noticing black-colored blood on the first day of their period. So, what causes black menstrual blood on day one?

What Causes Black Menstrual Blood on Day One?

Black menstrual blood on the first day may result from gynecological conditions or “cold uterus” (a Traditional Chinese Medicine concept referring to impaired uterine circulation due to cold). Conditions such as endometritis or uterine fibroids can lead to blood stasis. In such cases, not only does the menstrual blood appear very dark—or even black—on the first day, but the overall menstrual flow may also be noticeably darker throughout the cycle. Consuming cold foods before menstruation or abdominal exposure to cold may induce “cold uterus,” impair uterine blood circulation, cause congestion, and result in black menstrual blood and dysmenorrhea on the first day.

If black menstrual blood appears on the first day without accompanying symptoms, it is generally considered normal. However, if it is accompanied by abdominal pain, dysmenorrhea, or changes in menstrual volume, it may indicate menstrual irregularity requiring treatment with menstruation-regulating medications. Such conditions are typically manageable. Daily precautions include keeping warm to prevent cold exposure, avoiding spicy, raw, or cold foods. For dysmenorrhea, Dysmenorrhea Relief Granules may be taken regularly. For scanty menstruation, Bazhen Yimu Wan (Eight-Ingredient Motherwort Pills) may be used. Additionally, foods such as goji berries, longan, and lean meat may be beneficial.

Women are advised to stay warm during menstruation, maintain a positive emotional state, avoid cold exposure and cold foods, engage in moderate exercise, and refrain from overwork or strenuous physical activity. We hope this information is helpful to you.