Ulcerous impairments of gastric mucosa and an increase in activity of some enzymes in blood plasma were observed in rats after severe emotional-pain stress (EPS). The activity of cytoplasmic enzymes in blood plasma reached maximal values immediately after EPS and then returned to the initial level within the first day. At the same time, activity of lysosomal enzymes reached the highest values only at the end of the first day after EPS and their increased activity was maintained within 5 days. Ulcerous impairments of stomach as well as destruction of cellular membranes, responsible for an increase in the enzymatic activity in blood plasma, might be prevented by beta-adrenoblocking agent inderal. These data suggested that the impairments were due to the effect of excessive amount of catecholamines. Antioxidants dibunol and OP-6, administered prior to EPS, prevented the impairments caused by stress more effectively as compared with inderal; other antioxidants--alpha-tocopherol acetate and sodium selenite were less effective. The data obtained support the assumption on the leading role of lipid peroxidation in pathogenesis of the stress impairments; these data established that the impairments caused by stress might be prevented using the combination of antioxidants and beta-adrenoblocking agents.