The ability to express milk from the paratesticular breasts may be a symptom of mammary gland overflow, considering both physiologic and pathologic factors. 1. Physiological factors: If you can squeeze out milk during the breastfeeding period, it means that the development of the paramedical breasts is relatively complete and contains the tissues that should be present in the development of the breasts, which is a normal phenomenon. It can also be due to mammary hyperplasia, mainly due to the expansion of the ducts caused by mammary hyperplasia, which can lead to the phenomenon of the paratesticular breasts being able to express milk. 2. Pathological factors: such as pituitary adenoma, intraductal papilloma and other diseases. (1) Pituitary gland adenoma: the mammary gland overflows due to the increase of serum prolactin level caused by various reasons, and there is the phenomenon that milk can be squeezed out of the secondary breasts. (2) Intraductal papilloma: Breast overflow due to stimulation of glandular epithelium by papilloma, or breast overflow due to ductal dilatation, both of which may show milk extrusion from the breast. In daily life, if you find an unknown situation of milk extrusion from the paratoothed breast, you should go to the hospital in time to get a clear picture of the symptoms and get treatment under the doctor’s guidance.