The objective of the present study was to develop a rationale for the application of imudon (a bacterial lysate preparation)in the treatment of the patients presenting with chronic tonsillitis based on the elucidation of characteristics of local immunity in the oropharynx (determined from the results of cytograms, immunoenzyme assays for the quantitation of IgG, sIgA, IgA, and IgM antibodies, and calculation of the relative secretion coefficients). A total of 74 patients with chronic tonsillar pathology (24 children and 50 adults) were available for the observation along with 42 subjects having no tonsillar pathology with concomitant chronic bacterial rhinosinusitis. The control group was constituted by 25 practically healthy subjects. It was shown that the local application of imudon in the patients with the preserved function of palatine tonsils (in the absence of symptoms of chronic inflammation) produces the adequate response of the humoral and cellular immunity systems. In the patients with the simple form of chronic tonsillitis imudon therapy ensured statistically significant activation of congenital immunity including the phagocyte function and a tendency toward normalization of antibody formation. It is concluded that alteration of the function of palatine tonsils in the patients presenting with the toxico-allergic form (ТАФ-2) of chronic tonsillitis implies the necessity of surgical treatment (tonsillectomy).