The objective of this investigation was to assess immuno-, hepato- and actoprotective activity of mildronate and the impact of riboxin, elcar and essentiale on this drug in Wistar rats receiving the injections of sodium nitrite. The parameters characterizing non-specific resistance, immunological reactivity, the membranes state, detoxicating hepatic activity and physical performance. Mildronate administration increased functional activity of immune cells, hepatocytes and myocytes (but not up to normal limit) that had been reduced by sodium nitrite. The combination of mildronate and riboxine normalized phagocytic and metabolic activity of polymorphonuclear leucocytes, induced humoral immune response and delayed-onset hyperresponsiveness and normalized the ability of the intoxicated rats to perform submaximal physical activity. The combined administration of mildronate and essentiale normalized immune reactions, hepatic metabolism and physical performance of the rats poisoned by sodium nitrite. The combination of mildronate and riboxin or essentiale decreased the severity of damaged oxidation potential of the red blood cells of the intoxicated rats and prevented the development of erythrocytic immunosuppressive properties.