WHAT IS TONSILLITIS? Tonsillitis is a disorder involving inflammation of the tonsils. There are two tonsils, situated on either side of the back of the throat, and they form part of the body’s immune system. They like the rest of the immune system contains special cells to trap and kill bacteria and viruses traveling through the body. When the main site of infection is within the tonsils they swell, become red and inflamed, and may show a surface coating of white spots. Tonsillitis is extremely common in children and young people but can occur at any age. The characteristics of the disease are a pain in the throat and trouble swallowing. Tonsillitis is usually a self-limiting condition, i.e. it gets better without treatment and generally, there are no complications.