If a woman is breastfeeding or has just finished breastfeeding, it may be a normal overflow symptom. If the symptoms persist, or if the patient does not have a breastfeeding experience, such as men, unmarried women who are not pregnant and do not have children, the breast can squeeze out the white liquid, mainly related to the increase in serum prolactin levels, it is recommended to go to the hospital as soon as possible to improve the relevant examination. 1, abnormal nipple stimulation: nipple overflow symptoms are mainly regulated by serum prolactin, nipple or breast long-term external stimulation, through the body of various reflexes The process will lead to an increase in the level of serum prolactin, which in turn will cause abnormal breast can squeeze out white liquid; 2, hyperprolactinemia: pituitary lesions, hypopituitary lesions, hypothyroidism, liver cirrhosis, kidney disease and other diseases may cause the endocrine system and related hormone level disorders, inducing hyperprolactinemia, therefore leading to breast can squeeze out white liquid; 3, chest lesions: breast hyperplasia, breast duct dilatation, external chest Breast duct dilatation, chest trauma, local herpes zoster, intraductal papilloma, burns and other diseases can also stimulate an increase in serum prolactin levels and induce white fluid extrusion from the breast; 4, other: contraceptives, Valium, opioids and other drugs, as well as various drugs, may lead to an increase in serum prolactin release after a large intake, resulting in white fluid extrusion from the breast. There are many reasons that lead to increased serum prolactin levels and symptoms of white fluid that can be squeezed out of the breast, and most patients may not have other characteristic symptoms, so patients whose above symptoms persist and do not subside need to go to the hospital for relevant consultation and treatment as soon as possible.