Abstract: Rhizoma Dioscoreae Bulbiferae is a traditional Chinese medicine with hepatotoxicity, but the metabolic profile of fatty acids has not been identified in the rats with liver injury. In this project, a gas chromatography-mass spectrometry method was applied to simultaneous quantification of 16 non-esterified fatty acids (NEFA) and esterified fatty acids (EFA) in the serum of control, ethanol extraction of Rhizoma Dioscoreae Bulbiferae (ethanol extraction, ET) and diosbulbin B (DB)-treated rats. Meanwhile, the change of fatty acid metabolic profile of liver injured rats was analyzed by principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA). The results of NEFA concentration indicated that the serum concen-trations of palmitic acid (C16:0), stearic acid (C18:0), palmitoleic acid (C16:1n7), oleic acid (C18:1n9), vaccenic acid (C18:1n7), linoleic acid (C18:2n6), linolenic acid (C18:3n3), eicosatrienoic acid (C20:3n6), arachidonic acid (C20:4n6) and docosahexaenoic acid (C22:6n3) in DB-treated rats decreased significantly, while that of C18:2n6 and C20:3n6 obviously increased and that of C20:4n6 and C22:6n3 noticeably dropped in ET-treated rats when compared with control. Furthermore, the results of EFA concentration illus-trated that the serum concentrations of C16:0, C18:0, C20:4n6, C22:6n3 and eicosapentaenoic acid (C20:5n3) in two toxic groups were remarkably decreased when compared with control. The fatty acid meta-bolic profiles of the two toxic groups exhibited significant difference from the normal levels, and the degree of deviation of ET group was higher than that of DB group. More importantly, the results of PLS-DA showed that C20:4n6 and C22:6n3 were important indicators of the hepatotoxicity induced by ET and DB, and the serum concentrations of the two fatty acids had good correlation with the levels of alanine aminotransferase, aspartate aminotransferase and total bilirubin using Pearson's correlation analysis and canonical correlation analysis (CCA). Therefore, C20:4n6 and C22:6n3 were identified as potential biomarkers of ET and DB-induced liver injury. The project can provide a foundation for furture investigation of molecular mechanism of hepato-toxicity caused by Rhizoma Dioscoreae Bulbiferae.