Nipple overflow is one of the three major symptoms of breast disease, along with breast pain and breast lumps. Nipple overflow is a common breast disease, accounting for 5%-8% of outpatient visits for breast diseases, and can be divided into double breast overflow and single breast overflow, and multi-pore overflow and single-pore overflow. From the nature of the overflow, it can be divided into milk-like, plasma-like and bloody overflow, and from the cause, it can be caused by systemic and local factors. The most clinically significant would be the single-bore single-porous overflow, in which 90% of patients are caused by intraductal tumors, most of which are intraductal papillomas, and of course breast cancer. If nipple discharge is detected, it can be examined at a specialist hospital, usually by fiberoptic ductoscopy. Fiberoptic ductoscopy is performed on an outpatient basis and allows for a qualitative and localized diagnosis that is non-invasive and less painful.