Blood coming out of the breast is usually abnormal, which may be caused by trauma, intraductal papilloma, necrotizing inflammation of the milk ducts, etc. Trauma: because the breast tissue is fragile, when the patient suffers from trauma, it may lead to blood coming out of the breast. 1. Trauma: Because the breast tissue is relatively fragile, when the patient’s breast is traumatized, it may lead to the symptom of blood coming out of the breast. If the patient’s symptom is relatively mild, it usually does not need special treatment, and the symptom will gradually decrease with the growth of time. 2. Intraductal papilloma: If the patient suffers from intraductal papilloma, the tumor may protrude into the part of the milk ducts, which may lead to rupture of blood vessel wall for a long time, and then the symptom of blood coming out of the breast will occur. It is suggested that the patient should go to the hospital for examination to determine the cause of bleeding from the breast. 3. Necrotizing inflammation of breast ducts: Necrotizing inflammation of breast ducts may cause necrosis of breast ducts, which may destroy the surrounding capillaries, and when the capillaries are ruptured, the symptom of blood coming out of breasts will occur. At the same time, breast duct dilatation and breast cancer may also have bleeding. Careful identification is needed. It is recommended that patients should go to the hospital to find out the cause of the disease and standardize the treatment under the guidance of the doctor. And during the recovery process, comfortable and breathable underwear should be worn to avoid pressure on the breast.