Objective: We hypothesized that multiple organ injury and concentrations of xanthine oxidase (an oxidant-generating enzyme released after hepatoenteric ischemia) would be decreased by the administration of a bolus of a colloid solution at reperfusion. Design: Randomized, masked, controlled animal study. Setting: University-based animal research facility. Subjects: Fifty-four New Zealand white male rabbits, weighing 2 to 3 kg. Interventions: Anesthetized rabbits were assigned to either the hepatoenteric ischemia- reperfusion group (n = 27) or the sham-operated group (n = 27). Hepatoenteric ischemia was maintained for 40 mins with a balloon catheter in the thoracic aorta, followed by 3 hrs of reperfusion. Each group was randomly administered a bolus of one of three fluids at the beginning of reperfusion: Hextend® (herastarch solution); 5% human albumin; or lactated Ringer's solution. The investigators were masked as to the identity of the fluid administered. Measurements and Main Results: Multiple organ injury was assessed by the release of lactate dehydrogenase activity into the plasma and by indices of gastric and pulmonary injury. Circulating lactate dehydrogenase activity was significantly greater (p < .001) in animals receiving lactated Ringer's solution than in rabbits receiving either colloid solution. Gastric injury (tissue edema. Histologic Injury Score) was significantly decreased (p <.01) by administration of both colloid solutions. Lung injury (bronchoalveolar lavage lactate dehydrogenase activity) was significantly decreased (p < .05) by the herastarch solution administration. The hetastarch solution administration resulted in 50% less xanthine oxidase activity release during reperfusion compared with albumin or lactated Ringer's solution administration (p < .001). Conclusion: We conclude that multiple organ injury and xanthine oxidase release after hepatoenteric ischemia-reperfusion are decreased by colloid administration.