Many patients who come to the clinic will say she has fluid coming out of her nipples or find blood on her underwear and ask if this is normal. Surprisingly, some patients think that many people have it and consider it normal, which are obviously wrong views. In fact, except for breastfeeding women who have milk overflowing from their nipples, in general normal women do not have fluid overflowing from their nipples. Under what circumstances will nipple overflow occur? In general, there are several cases: First, women with enlarged milk ducts, in which case the nipple overflow is often a clear liquid (milky white or clear water-like, rarely bloody) and most of the water comes out of bilateral nipples with multiple holes, which is often accompanied by pain in the breast or nipple and is aggravated during menstruation. The second is abnormal lactogen production, which is characterized by non-lactating bilateral nipple discharge (mostly milky white milk), and requires lactogen and cranial CT to rule out pituitary tumors. Third, the most common clinical tumor in the milk ducts is often manifested as unilateral breast overflow from a single hole (which can be white, yellowish, greenish clear or cloudy fluid, or bloody, light bloody, coffee-colored fluid) This condition requires lactoscopy to rule out tumors in the milk ducts. In summary, non-lactating women who have nipple overflow should go to the hospital for professional consultation and treatment, and should not avoid avoiding medical treatment, so that minor illnesses do not become major illnesses.