The aim: Of the study was to study the activity of superoxide dismutase and catalase in the gastric mucosa of rats under long-term administration of omeprazole and combined administration of omeprazole with Symbiter and Apibact multiprobiotics.Materials and methods: The study was carried out on 40 white non-linear male rats with an initial weight of 160-180 g. All animals were divided into 4 groups. Group I was the control. Group II was administered omeprazole once a day within the period of 28 days. Group III was administered a combination of omeprazole and Symbiter® multiprobiotic. Group IV was administered a combination of omeprazole and Apibact® multiprobiotic. The activity of superoxide dismutase in cells was determined by Chevars et al. . The catalase activity in cells was determined by Korolyuk et al. . Statistical processing of the results was performed using the "Statistica 7.0" software.Results: The activity of SOD and catalase in the gastric mucosa of rats after 28 days of omeprazole administration increased compared to the control. Probiotics reduced the activity of SOD compared to the group of rats where omeprazole only was administered. The catalase activity in the gastric mucosa of rats which were jointly administered omeprazole and multiprobiotics for 28 days did not statistically significantly differ from the similar index in the control group.Conclusions: Prolonged gastric juice hypochlorhydria led to depletion of antioxidant protection enzymes. Multiprobiotics reduced the manifestation of the inflammatory process in the gastric mucosa.