Menstruation is the withdrawal bleeding of estrogen and progesterone from a woman’s body, while bleeding is the non-menstrual vaginal bleeding. The specific differences can be as follows: 1. Menstruation is regular and cyclical, while bleeding is irregular. 2. Menstruation is a normal physiological process for women, and bleeding is usually considered pathological, mostly irregular bleeding due to disorders of hormone levels in the body, which usually requires intervention. 3. Menstrual blood is a mixture of endometrial shedding accompanied by cervical mucus and epithelial cells shed from the vagina, dark red and The menstrual volume is in the range of 20-70ml. The bleeding is mostly bright red when the amount is high, and can be light red or dark brown when the amount is low.4. Menstruation is uterine bleeding, and the bleeding may be abnormal conditions such as uterine bleeding, cervical polyps, or cervicitis. Menstruation is a normal physiological phenomenon which does not require intervention, while bleeding, especially regular irregular vaginal bleeding, is recommended to be able to go to the hospital for timely examination and treatment.