Objective. To study clinical and pathophysiological symptoms of autonomic dysfunction syndrome in children and adolescents and assess the efficacy of its treatment with nooclerin. Material and methods. Fifty-three patients, aged from 10 to 15 years, with autonomic dysfunction syndrome were examined. All patients underwent neurological examination, assessment with the A.M. Vein’s questionnaire of autonomic disorders, the 10 point Visual Analogous scale for headache and fatigue, the Spielberger—Khanin scale for anxiety, Kerdo index, Hildebrandt’s coefficient, electrocardiography with clinoorthostatic test, electroencephalography, and TOVA psychophysiological test. Results and conclusion. The signs of the asthenic-autonomic syndrome were characteristic of the clinical picture of disease. EEG results demonstrated the deficit of activation effects, predominance of synchronized effects of thalamic structures which led to the insufficient activation of cortical structures. These data support the high efficacy of nooclerin.