Background. The relevance of this study is determined by the need for the scientifically sound substantiation of the possibility for the use of acidic mineral waters in the treatment of digestive diseases taking into consideration their widespread application in ethnomedicine, in particular in the Republic of Tuva. Aims. The objective of the present study was to elucidate the gastroprotective action of acidic mineral water from the Azhyg-Sug source (Republic of Tyva) on the experimental animals as exemplified by the model of ulcerogenesis under the conditions of immobilization stress. Material and methods. The experimental studies were carried out with the use of 32 white rats of the Wistar line. Ulcerogenesis was initiated by means of immobilization stress. We evaluated the pathomorphological characteristics of the gastric mucosa and the number of destructions based on the Pauls index. The state of the lipid peroxidation system and antioxidative protection were determined from the content of malon dialdehyde and reduced glutathione, extracellular catalase and superoxide dismutase activities in erythrocytes. Results. The study has demonstrated that the mineral water from the Azhyg-Sug source slows down the development of the inflammatory and destructive necrotic processes in the mucosa of the stomach of albino rats. The depth of erosion in the animals receiving mineral water was 2.3 and 3.4 times lower than in the control animals (p≤0.05). The antioxidant effect of mineral water was confirmed by the 14—20% decrease of the MDA concentration as well as by the increase of the catalase and superoxide dismutase (SOD) activities by 21—25% and 20—30% respectively in comparison with the control animals. Conclusion. The Azhyg-Sug mineral water has the strong gastroprotective influence on the experimental animals having the induced neurogenic ulcer. One of the mechanisms underlying the gastroprotective action of the investigated mineral water arises from its ability to inhibit the processes of lipid peroxidation with the simultaneous enhancement of the activity of the antioxidant system of the organism.