Nipple overflow is a common and frequent disease in outpatient work, and there are physiologic and pathologic differences. In addition to lactation during pregnancy and lactation of course, a small amount of nipple overflow can be seen during perimenopause, and these are physiological. It is generally more bilateral and is often a multiductal orifice overflow. Clinically, nipple overflow refers to a variety of disorders that cause a variety of sexual overflows, such as bloody, plasma, purulent, watery, milk-like, etc. The common causes are as follows: 1, endocrine disorders: the overflow is often lactic, watery or plasma-like, mostly bilateral multi-ductal orifice overflow. 2, intraductal papilloma: overflow is mostly bloody, plasmacy, and is the most common cause of papillary overflow among benign tumors, mostly single ductal port overflow. 3, cystic hyperplasia: mostly bloody or plasma overflow from multiple ductal openings of bilateral nipples. 4, ductal dilatation of the breast: plasmacytic is common, partly bloody, plasmacytic or purulent, and can be single or multiple ductal orifices overflow. 5.Papillomatosis: The overflow is similar to that of intraductal papilloma, but severe papillomatosis is a pre-cancerous lesion and should be taken seriously. 6.Inflammatory disease: mostly purulent overflow from multiple ducts. 7.Breast cancer: Among all overflows, if accompanied by lumps, about 1/3 of them are cancer; while breast cancer accounts for about 10% or more of the cases of nipple overflow without palpable lumps. Most of the breast cancers that only show overflow but no lump is formed are in the early stage, which is a good time to get good treatment results and should not be missed. According to some statistics, 50% of breast cancer patients over 50 years old have nipple overflow, especially in middle-aged and elderly women, which should not be ignored. No matter what the cause of nipple overflow is, it should be treated as soon as possible.