Asanguineous hyperthermic liver perfusion was performed in five and seven pigs for 30 and 45 min respectively. Laboratory data, including changes of liver enzyme levels and results of liver function tests, as well as morphological alterations of liver structure, were compared with data from a 45-min oxygenated hyperthermic liver perfusion. In the group undergoing asanguineous liver perfusion survival was four of five and five of seven animals. In the oxygenated group six of seven pigs survived. Liver enzymes and function tests in the two groups with a 45-min perfusion time were not significantly different. All enzyme and laboratory test values returned to normal within 1 week. Similarly morphological changes were reversible within 1 week. The results suggest that asanguineous isolated hyperthermic liver perfusion up to 45 min is feasible without damage to liver tissue.