Previous studies in isolated limbs using crystalloid perfusion solutions have shown that control of the initial reperfusion reduces postischaemic complications. However, no experimental study has been undertaken to evaluate the concept of controlled limb reperfusion experimentally in an in vivo blood-perfused model and to assess the local as well as systemic effects of normal blood reperfusion and controlled limb reperfusion. Of 20 pigs undergoing preparation of the infrarenal aorta and iliac arteries, six were observed for 7.5 h and served as controls; 14 others underwent 6 h of complete infrarenal occlusion. Thereafter, embolectomy was simulated in eight pigs by removing the aortic clamp and establishing normal blood reperfusion at systemic pressure. In six other pigs, the composition of the reperfusate and the conditions of reperfusion were controlled during the first 30 min, followed by normal blood reperfusion. Some 6 h of infrarenal aortic occlusion leads to a severe decrease in high-energy phosphates and muscle temperature, together with a slight increase in creatine kinase and potassium in the systemic circulation. Normal blood reperfusion resulted in severe reperfusion injury: massive oedema developed, the tissue showed a marked decrease in oxygen consumption, glucose consumption, tissue ATP, total adenine nucleotides, muscle pH and total calcium in the femoral vein. Furthermore, a massive increase was seen in plasma creatine kinase concentration and potassium, together with the development of muscle rigidity. In sharp contrast, initial treatment of the ischaemic skeletal muscle by controlled limb reperfusion resulted in normal water content, oxygen consumption, glucose consumption, flow and muscle rigidity. Furthermore, controlled limb reperfusion resulted in higher total adenine nucleotides content, less tissue acidosis, markedly reduced creatine kinase release, and potassium release as compared with that of normal blood reperfusion. This study shows that 6 h of acute infrarenal aortic occlusion will result in severe reperfusion injury (postischaemic syndrome) if normal blood at systemic pressure is given in the initial reperfusion phase. In contrast, initial treatment of the ischaemic skeletal muscle by controlled limb reperfusion reduces the metabolic, functional and biochemical alterations.