The nature of nipple discharge can be watery, plasma, bloody, lactic, or purulent. Among them, plasmacy, aqueous and lactic overflow are more common. Nipple overflow is divided into physiological overflow and pathological overflow. Physiologic overflow is mainly seen in women during pregnancy and lactation. Diseases of the body or local breast tissue that cause nipple discharge are pathological. The clinical term nipple overflow usually refers to pathological overflow. For patients with nipple overflow, mammography can be performed under mammography to show the lesions in the breast ducts. 2. Papillary overflow smear cytology examination is simple and quick, just squeeze out the nipple overflow, catch it with a slide, then scrape the end of the slide to make a smear, and then look for the lesion cells under the microscope. 3. Fiberoptic ductoscopy is inserted into the milk duct through the small hole of the patient’s nipple overflow, which can locate and diagnose the suspected lesion site under direct vision, and if there is chronic inflammation of the milk duct, it can be directly treated by flushing.