There are various reasons for yellow water in the breast, which may be caused by papilloma, breast cancer and inflammation of the breast. 1. Dilated milk ducts or intraductal papilloma. Dilatation of the human milk ducts occurs, leading to the development of papillomas, and yellow water will be present after the papillomas rupture. 2. Carcinoma in situ of the milk ducts. When the cancer spreads to the capillaries of the milk ducts, the milk ducts will bleed, and after the bleeding, there will be the phenomenon of brown or yellow liquid coming out of the breast. 3. Breast inflammation. If the breast is infected by bacteria and produces inflammation, yellow water will appear. In addition, there are physiological reasons for yellow water in the breasts, but the possibility of disease is greater. If you have the above symptoms, you should consult a doctor in time to clarify the specific reasons and treat your condition in time to avoid aggravation.