Cracked nipple is a superficial ulcer that occurs on the nipple during breastfeeding. It often occurs during the first week of breastfeeding and is more common in first-time mothers than in menstruating mothers. The reason for this is that the epidermis of the nipple is thin and tough, and there are many factors that can cause cracked nipples, and the common causes are: 1, the nipple is sunken or too small, making it difficult for the baby to suck, and nipple damage occurs when the sucking force is too great. 2, feeding is not correct, not the nipple and most of the areola into the baby’s mouth. 3, Excessive use of soap or ethanol drying agent and other irritants on the nipple. 4. Excessive milk secretion and overflow erodes the nipple and surrounding skin, causing erosion or eczema. 5, the baby oral motor dysfunction or oral inflammation, in the process of breastfeeding the nipple bite can also cause nipple cracking.