This chapter discusses diseases of tonsils and adenoids, where acute conditions of inflammatory diseases of tonsil include acute tonsillitis, peritonsillar abscess, intratonsillar abscess and lingual tonsil abscess. Chronic conditions of inflammatory diseases of tonsil include chronic or recurrent tonsillitis and chronic specific tonsillitis. Acute tonsillitis is an acute inflammation of faucial tonsil which is most commonly seen in children. Acute tonsillitis may be of acute catarrhal, acute follicular, parenchymatous or membranous type. Peritonsillar abscess or quinsy is a collection of pus in the peritonsillar space between the superior constrictor and capsule of the tonsil. Laryngeal diphtheria causes laryngeal obstruction, hoarseness, stridor, cyanosis and asphyxia. Acute circulatory failure may be due to myocarditis or peripheral circulatory failure. Infection of the adenoids may be called adenoiditis which is usually because of acute or chronic rhinitis, sinusitis or tonsillitis. Tuberculosis of the tonsils is suspected when cervical lymph nodes are found to have tubercular pathology.