Breast bleeding is usually caused by capillary damage to the breast, breast inflammation, excessive suction force of the breast pump, and in rare cases, it may be caused by breast tumors. 1. Breast capillary damage: capillary damage in the breast caused by improper breastfeeding and milking methods can lead to breast bleeding. The patient should promptly suck out the milk from the breast, keep the breast open and suspend breastfeeding; 2, breast inflammation: acute mastitis patients due to breast inflammation, can lead to local glandular congestion and edema, and even the performance of nipple bleeding, should promptly anti-inflammatory treatment, and those with swelling and pain can choose local hot compresses to help dissipate the inflammation; 3, excessive suction force of breast suction device: excessive suction force of breast suction device leads to mucosal damage to the milk ducts It is recommended to suck the breast as gently as possible; 4, breast tumor: malignant tumor of the breast can lead to bloody overflow, thus may bleed when sucking the breast, after the diagnosis needs to be surgical treatment, auxiliary radiotherapy and so on. If there is occasional breast bleeding, it is generally not a big problem. Usually, you should pay attention to observe and protect your breasts, as well as pay attention to maintaining breast hygiene. If breast bleeding occurs continuously, or is accompanied by abnormalities such as breast lumps and enlarged axillary lymph nodes, it may be a disease such as breast tumor, and it is recommended to seek medical diagnosis and treatment in a timely manner.