The effect of contrast media used for intravenous pyelography onto intracellular energy cycle ensymes was investigated. All types of nonionic contrast media inhibited succinatdehydrogenase and alfa-glycerophosphatdehydrogenase. This inhibition was less pronounced with Iodixanol injection. The way to prevent this metabolic changes is proposed and tested.Key words: Contrast media, intravenous pyelography, children