Abstract: AimTo study the effect of 3,4-oxo-isopropylidene-shikimic acid (ISA) on H₂O₂ (200 mol·L^-1, 4 h) injured human umbilical vein endothelial cells (HUVEC). MethodsMorphological change was observed under microscop. Cell viability was assessed by MTT assay. The release of intracellular lactate dehydrogenase (LDH) and NO was assessed by colorimetry. Radioimmunoassay was used to assess 6-keto-prostaglandin F1α(6-keto-PGF1α). ResultsPretreatment with ISA for 6 h alleviated the morphological damage of H₂O₂ induced HUVECs. At the concentration of 1-100 μmol·L^-1, ISA prevented the inhibitory effect on cell viability induced by H₂O₂ in dose-dependent manner, but increased the ratio of cell viability from 60.4% to 84.3%. ISA reduced LDH release and increased the level of NO and 6-keto-PGF_1αin H₂O₂ induced HUVECs. ConclusionISA exerted protective effect on H₂O₂ injured HUVEC.