It has been demonstrated that plasma from patients with fulminant hepatic failure (FHF) interferes extensively with cellular function. We placed primary human and primary porcine hepatocytes in a polyurethane foam (PUF)/spheroid culture system and compared the metabolic functions in the plasma of patients with FHF in a 24-h stationary culture to those in a monolayer culture. The PUF/spheroid culture system using primary human and primary porcine hepatocytes significantly decreased ammonia content during 28-day culture. Fisher's ratio significantly increased at culture days 3 and 7. Tauroursodeoxycholic acid significantly increased and glycochenodeoxycholic acid and taurochenodeoxycholic acid decreased in the FHF patients' plasma at culture day 3. During at least a 24-h culture in the FHF patients' plasma, metabolic functions of primary human and primary porcine hepatocytes were almost identical. The present results indicate that the PUF/spheroid culture system using primary human or primary porcine hepatocytes demonstrated more advantageous metabolic functions in the plasma from patients with FHF than the monolayer culture.