Nipple water is a very common symptom, milk will flow out from pregnant women in normal delivery, but if the nipple water is not flowing in this period, basically there is a problem. First of all, nipple water is divided into single or multiple holes according to the number of holes, passive and active according to whether or not it needs to be squeezed, and bloody, plasma, clear water and milk-like according to the nature and color of the water. In addition to lesions of the breast itself, other basic systemic problems or medications can also cause nipple discharge, mostly clear water or milk-like. For example, pituitary tumors or hyperprolactinemia can cause overflow, and long-term use of medications such as morbutine, tapazole, and antidepressants can also cause watery or lactic fluid from the nipples. However, most of these two conditions are porous. In the past, the main method of detecting such cases was to examine the overflowing fluid, but the positive rate was very low, with only 30% of the cases being diagnostically helpful, and the other method was to perform ductal imaging, hoping that some indirect signs would help the diagnosis. Of course, ultrasound and MRI are also used, but they are not very accurate at the moment. The lactoscopy that emerged in the 1990s has solved the shortcomings of the above examinations. Through a tiny endoscope, the diameter of which is even thinner than a toothpick, it is possible to clearly see what is happening in which part of the milk ducts, which is a clear guidance for surgery. We introduced this technology in 1999 and have completed nearly 4,000 cases and found more than 100 cases of early early breast cancer, which has improved the accuracy of early cancer diagnosis. We recommend paying extra attention to bloody overflow. According to our data, 10% of bloody overflow may be caused by breast cancer and 50% may be intraductal papilloma, both of which require surgery.