Extruding transparent liquid from nipple may be a symptom of breast cancer, but it may also be caused by intraductal papilloma, cystic hyperplasia of the breast, etc. The cause of the disease should be identified and treated symptomatically. 1. Breast cancer: mainly manifested as nipple discharge, breast lump, breast skin abnormality, nipple areola abnormality and other local symptoms, over-nutrition, obesity, high-fat diet, excessive alcohol consumption and so on may induce breast cancer. 2. Intraductal papilloma: the typical symptom is nipple overflow, when the volume of the mass is large, the mass can be touched, and a few patients can be accompanied by pain. Pregnancy, drugs or food may induce intraductal papilloma. 3. Cystic hyperplasia of the breast: the main clinical manifestations are breast lumps, some of which are accompanied by irregular breast pain, and a few patients may have nipple discharge. Breast cystic hyperplasia is related to ovarian endocrine stimulation. Clear liquid from the nipple may also be caused by physiological factors, when the symptoms appear, you should go to the hospital in a timely manner, identify the cause of the disease and follow the doctor’s instructions for treatment.