Abstract: This study was designed to investigate the correlation between idiosyncratic liver injury and content of cis-2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside(cis-SG)in radix Polygoni multiflori Preparata(RPMP). In order to compare the effect of hepatotoxicity of different cis-SG contents in RPMP, rats were administered with 50% alcohol extracts of RPMP(7.56 g·kg^-1, via intragastric administration)alone or co-treated with lipopolysaccharide(LPS, 2.8 mg·kg^-1, via tail vein injection). The results showed that no significant alterations of plasma ALT and AST activities were observed in the normal rats. In the LPS treated rats, the group without light treatment and the group with 0.10% cis-SG after light treatment did not exhibit obvious injury in liver. The group with 0.35% cis-SG after light treatment and the group with 0.70% cis-SG after light treatment showed significant increases in ALT, AST, TNF-α, IL-6, NF-κB p65 and apoptosis rate(P < 0.05), causing pathological changes in the liver tissue. Through the content analysis of drug in patients with liver injury, we found that the content of cis-SG(> 0.40%)was generally higher than that of pieces collected from different origins(< 0.10%). The comparative analysis of experiments and clinical data showed that there was a relationship between the content of cis-SG and idiosyncratic liver injury. In order to reduce the risk of clinical medication, the content of cis-SG of 0.10% should be a limit of quality control in the production processing of Polygonum multiflorum.