We clinically analyzed significance of serum human hepatocyte growth factor (hHGF) concentrations (ng/ml) before and after hepatectomies. We examined 39 hepatectomized patients (Group H) and 8 non-hepatectomized patients as control (Group C). In group H, hHGF levels elevated significantly on postoperative 1st, 3rd, 5th, and 7th days (0.59 +/- 0.24, 0.47 +/- 0.23, 0.38 +/- 0.16, 0.38-0.14, respectively) compared with the preoperative value (0.27 +/- 0.11). On the 3rd day hHGF levels in Group H (0.45 +/- 0.22) were significantly higher than those in Group C (0.30 +/- 0.06). Nineteen cases of 2-segmentectomy and 8 cases of partial resection showed significantly higher hHGF levels on the 3rd day than those in Group C. In 12 patients with liver cirrhosis, hHGF levels were significantly higher on the 5th and 21st days than those in 27 patients without cirrhosis. Three patients with hepatic failure showed significantly higher hHGF levels correlated conversely with preoperative serum albumin and hHGF levels on the 1st day after operation significantly correlated with operative time, blood loss during the operation. It was suggested that serum hHGF level correlated with hepatic functional reserve. We concluded that serial measurement of hHGF was useful for evaluation of postoperative damage of hepatic functions, and prolonged high hHGF levels might suggest hepatic failure.