The objective of the present study was to analyze the quality of nasopharyngeal sanation during the treatment of the children presenting with exacerbations of chronic adenoiditis with the use of different methods. Another objective was to estimate the influence of individual methods on the indigenous microflora. The study has revealed the prevailing groups of microflora in the nasopharynx, nasal cavity, and palatine tonsils of 2.228 patients. The clinical examination and comparative analysis of the results of the bacteriological study of nasopharyngeal discharge involved 170 children at the mean age of 5.06±2.6 years presenting with exacerbations of chronic adenoiditis. The patients of group 1 (n=60, control group) underwent nasopharyngeal sanation by means of the low-frequency ultrasound treatment, those of group 2 (n=53) were given an oral antibiotics (amoxicillin/clavulanic acid) at an age-based dose during 7—10 days. The patients of group 3 (n=57) were treated with bacterial lysate OM-85 BV (Broncho-Vaxom) (a 3.5 mg capsule once daily in the morning hours under the fasting condition for 3 months (during 10 days of every month). The amount of anaerobic bacteria in the control cultures from the patients of group 1decreased six-fold and that of pneumococci by 3 times. In the children comprising group 2 all pathogenic species persisted despite the treatment whereas in group 3 the number of those species largely decreased whose lysates were contained in the medication. In the patients treated with Broncho-Vaxom the beneficial results of therapy 1 and 3 months after its onset were more apparent than in the children of two other groups. Moreover, this preparation did not affect the indigenous microflora.