Mastitis refers to a suppurative disease caused by invasion of bacteria into the breasts. The pathogenic bacteria are staphylococcus aureus or streptococcus. This disease often happens in the primiparae less than one month after delivery. Its clinical characteristics are high fever, aversion to cold, mass in the breasts with local redness, swelling, heat and painful sensation, unsmooth lactation, and even pus discharge after rupture. It is believed in Chinese medicine that this disease belongs to the category of "Breast Carbuncle". The problem occurring during lactation is termed "external breast abscess" and the problem happening during pregnancy is termed "internal breast abscess".