There are congenital and acquired secondary nipple invagination. In case of congenital nipple invagination, the baby is not allowed to suck during breastfeeding, resulting in milk stagnation and mastitis. The way to prevent it is to return to the breast immediately after childbirth. To prevent mastitis from occurring. For incomplete nipple invagination, pay attention to nipple protection after delivery, keep it clean, and empty the remaining milk if there is milk retention after breastfeeding. Prevent the occurrence of mastitis. If breast leakage has formed during the non-lactation period and recurrent, surgery should be done to correct the invaginated nipple. It can be completely cured.