Brown menstrual blood is mainly due to the accumulation of blood in the uterine cavity without timely discharge. Menstruation is caused by the cyclical changes of hormone levels in the body, which leads to the shedding of the endometrium and bleeding. Brown menstrual blood without abdominal pain, increased menstrual volume and odor does not require special treatment. Avoid vaginal douching, bathing and sexual intercourse to prevent the introduction of external bacteria into the vagina, which can lead to reproductive system infections and even life-threatening infections in severe cases. During menstruation, it is important to take more rest, strengthen the nutrition intake, but avoid too much cold food, wear loose, comfortable and breathable underwear, avoid tight underwear, and keep your mood happy.