Occlusive ductal inflammation is an inflammatory condition caused mainly by bacterial infection of the mammary gland and milk ducts, dilatation of the milk ducts, and accumulation of breast milk. 1. Bacterial infection of the mammary gland and milk ducts: This may be due to the invasion of bacteria into the breast tissue, including hemolytic streptococcus, staphylococcus aureus, etc. Occlusive ductal inflammation is characterized by inflammatory lumps in the breasts, and symptoms such as swelling and pain may be present at the site of the lesion. 2. Dilatation of milk ducts: When the milk ducts are dilated, a large amount of secretion accumulates, causing pressure on the tissues, leading to infection and the formation of occlusive mastitis. 3. Breastmilk accumulation: Breastmilk accumulates during breastfeeding and cannot be passed on in time. Milk is a good bacterial culture agent, once infected, it will quickly cause occlusive mastitis. If occlusive mastitis is diagnosed, early and standardized treatment is recommended to minimize the adverse effects of the disease.