Nipple overflow is one of the common symptoms in mammography clinics and is more easily noticed by patients, and is one of the main reasons why about 10% of patients come to the clinic. Nipple discharge is mainly caused by physiological factors, systemic diseases and breast diseases. About 5% to 10% of breast cancer patients have nipple discharge, and about 1% of breast cancer patients have nipple discharge as the first or only symptom. Since malignant lesions are more likely to cause hemorrhage, patients with hemorrhage should be more alert to the possibility of malignant lesions. If nipple discharge occurs in male patients, it should not be taken lightly. The common examination methods for nipple overflow include nipple overflow smear cytology, mammography and endoscopy. The fiberoptic duct endoscopy (FDS) is composed of light source, image monitor, camera recorder, and fiberoptic mirror, and its outer diameter is only 0.7mm, which can directly see the changes in the epithelium of the milk ducts. It is of epoch-making significance for the qualitative and localized diagnosis of microscopic lesions in the milk ducts with bloody or plasma nipple overflow and no swelling accessible to the breast. Our breast surgery department is equipped with the latest generation of ultra-fine fiberoptic endoscopy system.