The objective of research was to study the state of prooxidant and antioxidant systems in the tissues of the lungs, kidneys, pancreas and salivary glands at burn disease. The intensity of the free radical processes was evaluated on the basis of the content of malondialdehyde (MDA) and antioxidant system – based on the indexes of its enzymatic chain: superoxide dismutase and catalase in homogenates of the studied organs. It has been found that changes in experimental burn disease depend on the studied organs and the stage of burn disease. The activation of free radical processes observed in all investigated organs (lungs, kidneys, pancreas and salivary glands). Reactive oxygen species induce lipid peroxidation, which is a universal marker of tissue damage. MDA appears in the body during degradation of polyunsaturated fatty acids and it’s a marker of lipid peroxidation and oxidative stress. It was found the increasing of MDA in all organs, especially in the lungs and kidneys at stage of burn shock. Under these conditions it was observed the decrease of superoxide dismutase and catalase in all investigated organs. At burn disease there is development of disbalance between the action of prooxidant and antioxidant systems due to the activation of free radical processes.