If the amount of fluid is relatively small, colorless and transparent or white, and there is no discomfort in the mammary gland, it is considered to be the normal secretion of the mammary gland, and can be observed for a period of time. If the extruded fluid is yellowish, and the mammary gland has pain and discomfort, and the amount of fluid is relatively large, it is also considered that there is inflammation of the mammary gland caused by infection in the milk ducts, and this kind of inflammation and infection, the secretion will increase significantly. Extruded fluid is brown bloody overflow, consider the breast ducts within the papilloma, papilloma wall thin, easy to rupture lead to bleeding situation, manifested as nipple bloody overflow. Breast cancer is also prone to bloody overflow due to its rapid growth and rich blood circulation, which can be touched by a lump in the breast. In either case, it is recommended to go to the hospital and let the doctor make a diagnosis.