The number of patients encountering nipple discharge in the clinic is increasing and some are panicking. It is important for me to make it clear to everyone here that most nipple discharge is actually nothing to be afraid of. The nature of nipple discharge is varied, and the primary lesion causing the discharge can be different. The nature of the disease can be inferred from the nature of the nipple overflow, combined with clinical examination and signs. There are several common types of nipple overflow: 1. Milk-like overflow: this type of overflow is colored like de-fatted milk, often occurring years after weaning, and is generally bilateral. The sustainability of the overflow can be caused by pituitary tumors, but also by endocrine disorders regulated by the nervous system governed by the hypothalamus, caused by elevated lactogen, and some mastopathy will also appear overflow phenomenon. 3, purulent overflow: common postpartum acute mastitis, the nipple has purulent secretion from the nipple outflow, yellow-green color, culture is often Staphylococcus aureus growth, must be treated to continue breastfeeding, repeated episodes must be weaned, or cause adults and infants are disadvantaged. 4, watery overflow: the overflow is thin and clear watery overflow, mostly caused by cystic mastitis, but also by fibrocystic disease or intraductal papilloma. 5, plasmacytic, plasmacytic blood and bloody overflow: plasmacytic is pale yellow, we depict straw color, plasmacytic blood is pinkish, bloody is dark red or coffee color. This kind of overflow should be taken seriously and close attention should be paid to whether there are traces on bras and underwear. Most of my experience is caused by intraductal papillary tumors, and a few are caused by intraductal papillary carcinoma, accounting for about 10%. Bloody overflow in patients over 60 years old may be caused by ductal carcinoma of the breast, accounting for about 30-45%. Distinguishing the nature and color of nipple overflow can help identify and treat nipple overflow disease, and must be seen by experienced doctors in specialized hospitals.