Purpose : Although the liver is an important source of IL-6 and the primary site for its clearance, the role of IL-6 in liver disease remains unclear. Warm ischemia/reperfusion (WI/Rp) injury to the liver occurs in numerous clinical situations including liver transplantation and surgery, trauma, hemonhagic and endotoxic shocks, and thermal injury. A better understanding of the pathogenesis of WI/Rp injury of the liver and the availability of an agent that could alleviate Rp injury would have important clinical implications. The aim of this study was to evaluate the role of IL-6 in WI/Rp injury of the liver. Methods : Thirteen patients who had undergone hepatectomy were evaluated with regard to postoperative changes in serum IL-6. The measurements were performed before surgery, within 30 minutes after WI/Rp injury, and at postoperative 24 hr, 48 hr, 1 wk, 2 wk, and 4 wk. Seven of 13 patients had the complication of cirrhosis. Results : The mean value of IL-6 was 8.13 pg/ml preoperatively, and peaked at 20.51 pg/ml on the first postoperative day. Serum IL-6 levels within 30 minutes following WI/Rp injury and at postoeprative 1 day were higher in patients with cirrhosis than non-cirrhotic patients, although statistically insignificant. In the case of the cirrhotic patients, IL-6 values on the first postoperative day peaked at 40.81 pg/ml, compared to 35.27 pg/ml in non-cirrhotic patients. SGOT and SGPT were consistentiy increased with IL-6 on the first postoperative day, and gradully decreased thereafter. Conclusion: This study shows that IL-6 may be an indicator in WI/Rp injury of the liver. Procedures undertaken to reduce the excessive produciton of this cytokine may be useful of improving postoperative liver fuction with or without cirrhosis. (J Korean Sung Soc 2001;60:320-323)