Background/Aims: Hepatocyte growth factor, a potent mitogen for mature hepatocyte in vitro, seems to function as liver regeneration. Although many studies on human hepatocyte growth factor(hHGF) are being conducted, its clinical significance remains unclear. We measured the serum hHGF levels in patients with various liver condition to evaluate its clinical significance including liver injury and regeneration. Methods: We rneasured serum hHGF levels and its changes by enzyme linked immunosorbent assay(ELISA) kit in 59 patients with hepatitis(five groups: 9 acute hepatitis, 12 chronic hepatitis, 17 liver cirrhosis, 10 acute hepatic failure, 11 chronic hepatic failure) cornpared with 10 normal subjects and 10 chronic renal failure. We also measured the changes of serum hHGF concentration with regular interval in 11 patients with hepatocellular carcinoma after transarterial chemoembolization(TACE; 9 patients) and partial hepatectorny(2 patients) and in 2 patients with chronic active hepatitis who ha3 steroid-interferon (IFN) administration. Results: Serum hHGF levels in each group of hepatitis were significantly higher than those in normal subjects(p<0.05). Furthermore, those in patients with acute hepatic failure were significantly higher than those in any other groups(P<0.05). In patients with acute hepatitis, serum hHGF level decreased with recovery of hepatic function. The .'erum hHGF levels in patients with acute hepatic failure steadily increased until the patient died ar,d those in patients with chronic hepatic failure decreased with recovery from hepatic coma. The serum hHGF levels in the various liver diseases were well correlated with tota] bilirubin and prothrombin time., but not with AST, ALT, and albumin. It was on the 2nd day that the serum hHGF level most increased after TACE or partial hepatectomy in patients with hepatocellular carcinoma but the time of most increased level of serum ALT was the 3rd day. The serum hHG,"" levels in patients with chronic active hepatitis treated with interferon a 2b after steroid administration decreased during steroid administration, and increased during interferon therapy. Conclusions: Based on these results, the serum hHGF level is proven to be a indicator for the degree of liver function, but not as an indicator of the degree of liver injury or regeneration. Serial ass,iy of serurn hHGF levels are considered to be a useful prognostic factor in active and chronic liver diseases. (Korean J Gastroenterol 1997; 30:611-619)