When nipple discharge is detected, it is important to understand whether it is self-spilling or extruding. In the case of spontaneous overflow, pathologic conditions are common. For example, in menopausal or near-menopausal women taking birth control pills or depot treatment, a small amount of cloudy, milky or thick, slightly grayish discharge is often seen when the subareolar tissue or nipple is squeezed. In the case of nipple discharge, it is important to distinguish between true or false discharge. Genuine is ductal discharge, while pseudo can be due to nipple erosion, nipple trauma, Paget’s disease, or discharge from a ductal fistula due to recurrent infections. In nipple overflow, most of them are intraductal papilloma, and the malignant ones account for about 10%. (1) Milk-like overflow: it is a continuous, non-transferable bilateral spontaneous nipple discharge with the color of defatted milk, which is often concomitant with amenorrhea, and it can also occur in women with normal ovarian function or be caused by certain medications, such as contraceptives, sedatives, and so on. The reason is that the hypothalamus weakens the inhibition of pituitary gland and the pituitary prolactin increases. (2) Watery overflow: clear and transparent watery overflow often suggests the possibility of malignant lesions and should be operated as soon as possible. (3) Plasma, plasma blood and blood overflow; plasma is mostly yellowish, plasma blood is reddish or brown, and blood is red or brown. Commonly seen in fibrocystic hyperplasia, intraductal papillomas, progressive ductal dilatation, and breast malignancies, but occasionally seen in breasts that are significantly engorged with pregnancy. about nearly half of patients over 60 years of age are breast cancer patients. Surgical biopsy should be performed as early as possible in patients with plasma, plasma hemorrhagic and hematogenous overflow. (4) Mucous fluid overflow: thick and sticky secretion, redness, burning pain, itching and swelling of nipple and areola at the same time. Under the areola, it can be touched with earthworm-like sensation, which mostly occurs in patients with ductal dilatation or plasma cell mastitis and acne-like breast cancer, and plasma, plasma hemorrhagic and hemorrhagic overflow can occur if it continues to develop. This disease is common in menopausal or near-menopausal patients, but also in young women with hypogonadism, and patients have the habit of touching their nipples frequently. Therefore, attention should be paid to nipple cleaning in the early stage, avoid touching the nipple, and appropriate estrogen treatment should be given, such as accompanied by lumps should be clearly diagnosed by surgical exploration as soon as possible. (5) Purulent overflow: Most common in acute mastitis, chronic mastitis during lactation, centralized abscess and plasma cell mastitis.