A simple and quick quantitative analysis of saikosaponins a, c and d, the major bioactive principles contained in Bupleurum species, by TLC scanner is described. Results with Bupleurum kaoi, the species native to Taiwan, showed that the roots, rhizomes and aerial parts (leaves and stem) have greater quantities of saikosaponins than cultivated B. falcatum var. komarowi and imported B. chinense. The liver protective effects of water extracts of "Xiao-Chai-Hu-Tang" (XCHT), a mixture of seven crude drugs, prepared using roots of the three different Bupleurum species and aerial parts of B. kaoi and B. falcatum var. komarowi, were evaluated using CCl4-induced toxicity in rats. The acute increase of serum transaminase (SGOT and SGPT) levels caused by CCl4 administration (3.0 ml/kg, s.c.) was dramatically reduced when treated with XCHT prepared with the roots of B. kaoi. The histological metamorphoses such as fatty changes, ballooning degeneration, cell necrosis and lymphocyte and Kupffer cell increases around the central vein, were clearly decreased by XCHT prepared with B. kaoi. Furthermore, water extracts of aerial parts of both B. kaoi and cultivated B. falcatum var. komarowi decreased SGOT and SGPT levels and moderately reduced the pathological changes.