The breast is an organ with secretion function, usually there is secretion through the breast ducts and nipples, and during lactation there will be milk discharge, the nipple opening is very easy to have bacterial invasion causing infection, inflammation in the milk ducts and nipples, and there is purulent discharge, you need to do a lactoscopy, according to the specific infection situation The ducts should be lavaged or treated with oral antibiotics. Plasmacytosis can also cause discharge from the nipples, which is an autoimmune disease in the human body and is prone to recurrent infections. Some patients with cystic hyperplasia of the breast may also have yellow discharge from the breast ducts, and when there is abnormal discharge from the nipples, you need to go to the hospital to check the specific cause.