Lactational mastitis is an inflammatory reaction of the mammary gland triggered on the basis of milk stagnation caused by various reasons, mainly due to milk stagnation and bacterial invasion. For those who have recurring breastfeeding mastitis, localized hot compresses are used to promote the dissipation of inflammation for those who have significant breast swelling or lump formation. For those with milk stagnation, localized hot compresses can be applied and the milk can be sucked out with a breast pump. 1. Milk stagnation: Because milk is a bacterial culture medium, milk stagnation will cause the growth and reproduction of invasive bacteria. Nipple dysplasia, excessive milk, low suckling by babies, and incompetent milk ducts will all affect milk discharge and lead to milk stagnation. 2. Bacterial invasion: The causative organisms of breastfeeding mastitis are mainly staphylococcus and streptococcus. The main reason for this is that the nipple is broken or cracked, so the bacteria invade along the lymph ducts and cause an infection. Bacteria can also directly invade the milk ducts and travel up to the glandular lobules and cause infection. Patients who suffer from breastfeeding mastitis that keeps recurring should go to the hospital in time and follow the doctor’s advice to choose the appropriate way of treatment.