Bacteria enter the eardrum and cause suppurative infection, which is called acute suppurative otitis media. It is mostly secondary to upper respiratory tract infection. Some cases may be initially infected by viruses, followed by bacterial invasion. Common ones are hemolytic streptococci, Staphylococcus aureus, type III pneumococcus and Proteus. It is more common in winter and spring, and is easily induced by patients with blood diseases, malnutrition, allergies, cardiopulmonary diseases, nephritis and diabetes. According to statistics, the incidence rate of school-age children aged 5 to 16 is as high as 3%, and that of those under 5 years old is as high as 5% to 10%, and sometimes it can recur many times. The incidence rate of Eskimos and American Indians is much higher than that of white people. It has not yet been determined whether this is due to racial genes or living conditions.