A short term application of a hybrid liver support system in circuits with continuous plasma-separation was investigated in a model of hepatectomized pigs under general anesthesia. Primary pig hepatocytes were immobilized in a bioreactor with three independent capillary systems. An immune barrier is achieved by avoiding the direct contact of blood cells with the hepatocytes by a plasmaseparation step and by an outflow filtration within the reactor. In three groups (hepatectomized pigs and system with- or without hepatocytes as well as untreated pigs with system without hepatocytes), the short term metabolism of the reactors was positively demonstrated by investigating ammonia detoxification, phenylalanine- and lactate metabolism. Limitations of the presented model are discussed.