Inflammation of tonsils may be caused by pathogenic microorganisms infection, decreased immunity, inflammation of neighboring organs, acute infectious diseases and other factors. 1. Pathogenic microbial infection: Infection by pathogenic microorganisms such as bacteria, viruses and parasites can lead to tonsil congestion, edema and inflammatory reaction, resulting in tonsillitis. 2. Decreased immunity: when the body’s immunity is decreased, pathogenic microorganisms will proliferate and multiply in the mouth and throat, inducing tonsillitis. 3. Inflammation of neighboring organs: Inflammation of organs around the tonsils, such as pharyngitis, laryngitis, rhinitis, etc., may infect the tonsils and lead to tonsillitis. 4. Acute infectious diseases: scarlet fever, diphtheria, measles, influenza and other infectious diseases may also cause tonsillitis. Patients are advised to go to the hospital for treatment in time.