Objectives : The aim of this study was to characterize the effect of Injinchunggan-tang on $TGF-{eta}1-induced$ hepatic fibrosis. Methods : mRNA and protein expression levels of $TGF-{eta}1$ in Injinchunggan-tang-treated HepG2 cells were compared to untreated cells using quantitative RT-PCR and ELISA assay, respectively. mRNA expression levels of the TGF-1 pathway genes (TR-1, TR-II, Smad2, Smad3, Smad4, and PAI-1) and fibrosis-associated genes (CTGF, fibronectin, and collagen type 1) were evaluated by quantitative RT-PCR. The effect of Injinchunggan-tang on cell proliferation of T3891 human fibroblast was evaluated using [$^3H$]thymidine incorporation assay. Results : Expression of $TGF-{eta}1$ mRNA and protein was inhibited by Injinchunggan-tang in a dose- and time-dependent manner. Whereas $TGF-{eta}1-mediated$ induction of PAI-1 was suppressed by Injinchunggan-tang, expression of the $TGF-{eta}1$ pathway genes such as TR-1, TR-II, Smad2, Smad3, and Smad4 was not affected by Injinchunggan-tang treatment. Injinchunggan-tang was found to inhibit $TGF-{eta}1-induced$ cell proliferation of T3891 human fibroblast, and also abrogated $TGF-{eta}1-mediated$ transcriptional up-regulation of CTGF, fibronectin, and collagen type I. Conclusions : This study strongly suggests that the liver cirrhosis-suppressive activity of Injinchunggan-tang may be derived at least in part from its inhibitory effect on $TGF-{eta}1$ functions, such as blockade of $TGF-{eta}1$ stimulation of fibroblast cell proliferation and fibrosis-related gene expression as well as expression of $TGF-{eta}1$ itself.