AIM: To elucidate the impact of hemodynamic parameters on ultrasonography and serum fibrosis markers for the assessment of liver fibrosis in the children with infant hepatitis syndrome (IHS).METHODS: Forty-one children with IHS and 46 healthy infants were examined by ultrasonography, and several hemodynamic indices such as peak systolic velocity (PSV) and resistant index (RI) of proper hepatic artery (PHA) were measured. Serum fibrosis markers including hyaluronic acid (HA), pre-collagen type-Ⅲ (PC-Ⅲ),collagen type Ⅳ (C-Ⅳ), and laminin (LN) were assayed by radioimmunoassays. In children with IHS, liver tissues were obtained either by ultrasound-guided liver biopsy (n = 35) or in the course of operation (n = 6).The stages of hepatic fibrosis were scored as mild (S1 and S2), moderate (S3), or severe (S4) according to liver histological diagnosis. Multiple groups comparative and Spearman correlative analyses were carried out. RESULTS: Histopathologically, 39 children (95.1%) were found to have hepatic fibrosis, 12 of them stage S1 or S2, 12 stage S3, and 15 stage S4. PSV, RI of the PHA,and serum HA showed a consecutive increase from mild to severe hepatic fibrosis and a close positive correlation with hepatic fibrosis in IHS group (r = 0.717, 0.745 and 0.712, respectively, P = 0.001). The Doppler waveform of HV was also positively correlated with the degree of hepatic fibrosis in IHS group (r = 0.783, P ＜ 0.001).CONCLUSION: Combination of ultrasonic studies on the hepatic hemodynamics with the evaluation of serum HA may provide an indicator for hepatic fibrosis in patients with IHS. This may be a useful noninvasive method for the diagnosis and evaluation of the prognosis of IHS.