Background: Cumulative data show the involvement of oxidative stress in pathogenesis of asthma. The aim of the study was to investigate the influence of anti-asthma treatment on oxidative stress intensity and the capacity of antioxidative defense in children with asthma.Material/Methods: Fifty-six children with stable,persistant mild asthma were included in the study. The subjects were divided into subgroups: I –with inhaled corticosteroids and long acting beta -agonists (15 patients), II-with long acting beta -agonists (2 patients), III–with inhaled corticosteroids (12 patients), IV –without any medication (27 patients). The control group comprised of 30 healthy children. The plasma protein carbonyls content, as a marker of oxidative stress intensity, was assayed using Levine method. SOD activity was measured in reaction with xantine-xantine oxidase. Results: Plasma protein carbonyls in patients with long acting beta -agonists (0.92 nmol/mg protein) was lower than in patients without such a treatment (1.0 nmol/mg protein 4)(p

Keywords: Asthma, children, treatment, antioxidative capacity, protein carbonyls