The palatine tonsils are part of the pharyngeal lymphoid ring, along with the tubal, pharyngeal and lingual tonsils. Because of their location at the beginning of the aerodigestive tract, they are constantly exposed to harmful environmental influences, and therefore susceptible to infections. Tonsillitis, inflammation of the tonsils, most often occurs in children. It is typically a viral infection and requires only symptomatic treatment. In 15 to 30% of cases the infection is bacterial and treated with antibiotics. Most cases of bacterial tonsillitis are caused by group A beta-hemolytic Streptococcus pyogenes. Streptococcal pharyngitis is diagnosed using the Centor criteria, rapid test and culture. The Centor criteria include temperature above 38°C, tonsillar exudate, tender anterior cervical lymphadenopathy, and absence of cough. Complications of tonsillitis include abscess formation in the peritoneal, parapharyngeal, and retropharyngeal areas. In case of unsuccessful conservative treatment, the other option is tonsillectomy. Tonsillectomy is a relatively safe procedure, but it removes an important part of the immune system, so it should be appropriately indicated.