Patterns of lipid peroxidation, chemoluminescence and anti-radical activity of rat blood serum were studied after simulation of visceral-ischemic shock developed as a result of two-hour-long ischemia of the small intestines and of right-side part of large intestine. Toxic effects of oxygen, accompanied by considerable activation of lipid peroxidation, were of importance in pathogenesis of this shock. Accumulation of lipid peroxidation products in blood occurred at the step of the instestine ischemia and was distinctly increased after restoration of circulation in the tissue. Increased inhibition of blood serum chemoluminescence as well as elevation of lipid antiradical activity were observed depending on steps of the shock development.