The subject of this study was to evaluate the activity of highly reactive oxygen species peroxidation products and antioxidants in patients with antral gastritis and positive Helicobacter pylori infection. The above mentioned parameters were monitored during two periods – before and after therapy. The results did not show, that H. pylori infection induces any changes in antioxidant balance. The patients with antral gastritis and positive H. pylori infection had specific disturbances in antioxidant balance, which were not significantly influenced by therapy. Because the individuals with disturbances in antioxidant balance had a modified response during infection, such patients could be also more susceptible to H. pylori infection.

        Key words: reactive oxygen species, antioxidant balance, peroxidation, Helicobacter pylori infection, macro-