Clear water coming out of breasts may be caused by milk secretion from milk ducts, dilatation of breast ducts, cystic hyperplasia of breasts, etc. It is suggested that patients should take treatment according to their own causes. 1. Milk secretion from the milk ducts: If the patient is in lactation or pregnancy, clear water from the breasts may be a normal phenomenon, because the placenta may secrete a large amount of estrogen during pregnancy, which stimulates the development of the milk ducts, and the breasts will secrete milk to prepare for the baby’s breastfeeding. 2. Dilatation of the breast ducts: Dilatation of the breast ducts, also known as plasma cell mastitis, is usually due to poor development of the mammary glands, resulting in estrogen, so the secretion of the milk ducts will increase, and a series of symptoms such as clear water extruded from the breasts. 3. Breast cystic hyperplasia: Breast cystic hyperplasia is a benign lesion that occurs mostly in middle-aged women, usually due to cysts caused by localized expansion of the ducts of the breast, and the patient may experience pain and swelling of the breast and secretion of fluid. It is recommended that patients should go to the hospital in time when they feel unwell.