OBJECTIVE:To evaluate the efficacy of Huanglian root decoction(黄连煎剂,HLD)on kidney injury in rat’s model of metabolic syndrome(MetS),and in-vestigate the possible mechanism.METHODS:A fructose-induced MetS rat model and human renal tubular epithelial cell-line model were used to compare the efficacy of HLD with that of berberine and tauroursodeoxycholic acid(TUD-CA).Blood pressure,biochemical parameters,histo-pathological changes and the expression levels of oxidative stress markers were evaluated in the an-imal model at the end of an 8-week treatment regimen.Oxidative stress markers and molecules of the signal pathway of endoplasmic reticulum(ER)stress were evaluated in the human cell-line model.RESULTS:Levels of fasting insulin,systolic blood pressure and diastolic blood pressure were signifi-cantly decreased in rats in the Huanglian group compared to those in the MetS group(P＜0.05).Rats treated with HLD and TUDCA exhibited a sig-nificant reduction in blood levels of malondialde-hyde compared to those in rats in the MetS group(P＜0.05).Significant increases in glutathione per-oxidase in human tubular epithelial cells was found in the Huanglian group compared to that in the MetS group(14.02 vs 18.31,P＜0.05).The mRNA ex-pression of protein kinase RNA-like endoplasmic re-ticulum kinase and eukaryotic translation initiation factor 2 α decreased significantly in Huanglian groups compared with that in the MetS group.CONCLUSION:HLD has therapeutic efficacy on kid-ney injury in the MetS rat’s model,and is non-inferi-or to berberine and TUDCA.