The causes of nipple overflow can be physiological, such as lactation in pregnant women, nipple overflow in menopausal women, nipple overflow after taking oral contraceptive pills, etc. It can also be pathologic, such as mammary hyperplasia, intraductal papilloma, plasma cell mastitis, breast cancer, lactinoma, etc. It is recommended to go to the hospital for medical consultation and treatment under the direction of the doctor. 1. Physiological reasons: when the sex hormone content in the body is disturbed, such as the increase of sex hormone secretion during pregnancy, the decrease of sex hormone secretion during menopause, and the increase of hormone intake during oral contraceptive pills, it will also lead to the occurrence of nipple overflow. 2. Pathological causes:The overflow of breast hyperplasia is often yellowish or colorless plasma, the overflow of intraductal papilloma and breast cancer is often bloody, plasma cell mastitis is often brownish in color, and prolactinoma is mostly colorless plasma. Careful differentiation is needed. It is recommended to visit the hospital, improve the examination, and make a clear diagnosis under the guidance of the doctor.