Introduction. Hypertrophy of the pharyngeal amygdala and associated retronasal obstruction play a key role in the pathogenesis of recurrent and chronic nasal and paranasal diseases in children. Medical literature has a limited number of publications devoted to the study of pre-nosological changes in morphofunctional status, which determine the adequacy and effectiveness of treatment. The goal of this study is to reveal symptoms of oxidative stress of the pharyngeal tonsil tissue during remission of chronic adenoiditis. Patients and methods. In the study, children aged 3—15 with clinical and anamnestic signs of chronic adenoiditis, including 3rd degree hypertrophy of adenoid vegetation, participated in planned surgical treatment. The examination consisted of the following 3 stages: listening to the patients’ complaints; examination of the patients’ ENT using instruments; and determining the levels of lipid peroxidation products, and spontaneous and metal-catalyzed oxidative modifications of proteins in the tissue of adenoid vegetation. The patients were divided into 2 groups. The first group included children suffering from only 3rd degree hypertrophy of the pharyngeal amygdala (n=19); the second group included children with 3rd degree hypertrophy of the pharyngeal amygdala combined with either 2nd or 3rd degree hypertrophy of the palatine amygdala (n=13). Results. The level of early markers of oxidative protein destruction in both groups was almost identical. However, the number of late markers was greater in the second group, indicating the prevalence of oxidative processes in the pharyngeal amygdala tissue. A higher reserve-adaptation potential was characteristic of the first group of patients, testifying to the relative safety of their defense mechanisms, in contrast to patients in the second group. Conclusion. For patients whose chronic adenoiditis is in remission while still displaying hypertrophy of the adenoids and palatine tonsils, the oxidative destruction of proteins in adenoid vegetation may still get the upper hand, which can be both a consequence and a cause of a more severe disease course. We consider it logical to assume, against the background of a relative decrease in the level of reserve-adaptation potential, that the easing of the inflammatory processes in the pharyngeal amygdale will continue, due to the accumulation of free radical oxidation with cytotoxic and chemoattractant properties. The data collected in this study testify to the potential for progress in the search for additional therapeutic and prophylactic methods aimed at optimization of free-radical oxidation in adenoid vegetation tissues when chronic adenoiditis is in remission.