Objective To evaluate the effect of methylprednisolone on hepatic ischemia-reperfusion (I/R) injury in the patients undergoing hepatolobectomy.Methods Sixty ASA physical status Ⅱ or Ⅲ patients,aged 30-64 yr,weighing 45-75 kg,scheduled for elective hepatolobectomy,were randomized to control group or methylprednisolone group (n =30 each).After induction of anesthesia,methylprednisolone 500 mg (in 100 ml of normal saline) was infused intravenously at 5 ml/min before skin incision in group M.Anesthesia was induced with propofol,fentanyl and cisatracurium.The patients were endotracheally intubated and mechanically ventilated.PETCO2 was maintained at 35-45 mmHg.Anesthesia was maintained with 1％-3％ sevoflurane inhalation,remifentanil infusion,and intermittent iv boluses of fentanyl and cisatracurium.MAP was maintained at 70-100 mmHg and HR at 50-90 bpm.At 10 min before induction of anesthesia,and on postoperative day 1,3 and 5,venous blood samples were collected for determination of the plasma levels of alanine aminotransferase (ALT),aspartate amminotransferase (AST),total bilirubin (TBIL),tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6).Results Compared with group C,the plasma levels of ALT,AST and TBIL were significantly decreased on postoperative day l and 3,and the plasma concentrations of TNF-α and IL-6 were decreased on postoperative day 1,3 and 5 in group M.Conclusion Methylprednisolone can reduce hepatic I/R injury in the patients undergoing hepatolobectomy and inhibition of systemic inflammatory responses is involved in the mechanism.