The yellow fluid that breaks the skin on the side of the chest during puberty may be physiological fluid and pathological fluid such as mastitis and eczema. 1. physiological overflow: during puberty, the high level of estrogen in women’s bodies will lead to hypersecretion of the mammary glands, which may cause the nipples to secrete less yellow liquid, which is a normal physiological phenomenon. 2. Pathological overflow: (1) Mastitis: the breasts have the function of secretion, usually there will be secretion from the breast ducts, when the bacteria invade, the nipple yellow overflow will appear. (2) eczema: yellow water flow is because of the local skin inflammatory reaction, caused by the expansion of small blood vessels in the skin, blood tissue fluid through the small blood vessels endothelial cells of the gap outward seepage to the outside of the cells, outside the blood vessels to form blisters, blisters rupture there will be obvious oozing, the symptoms of yellow water flow. If the symptoms of yellow water flowing from the broken skin on the side of the chest in puberty appear, and continue to be unrelieved, you need to seek medical treatment in time.