Aim: The objective of this study was to examine the effects of perioperative administration of ulinastatin, or urinary trypsin inhibitor (UTI), on inflammatory cytokines and acute-phase proteins induced by inflammatory cytokines in patients who had undergone hepatic resection, Method: Twenty patients admitted to the hospital for hepatic resection were equally randomized to one of two groups: the UTI group, those who were administered perioperative UTI, and the control group. Results: The UTI group had no adverse effects from using UTI, Production of serum interleukin-6 (IL-6) tended to be attenuated in the UTI group when compared with the control group. Moreover, the UTI group had significantly decreased positive acute-phase C-reactive protein (p < 0.05) and significantly increased negative acute-phase protein prealbumin and retinol-binding protein (p < 0.05), Serum IL-6 levels significantly correlated with serum C-reactive protein levels on postoperative day 1 (r = 0.70, p < 0.01). Conclusion: These results suggest that perioperative administration of UTI might deserve further assessment for use in modulating acute-phase responses without adverse effects in patients who have undergone hepatic resection, Copyright (C) 2000 S. Karger AG, Basel.