Abstract: ObjectiveTo probe the cytotoxicity of kojic acid to established cell lines.MethodsTwo cell lines,Vero cell and CHO-K1 cell,were treated with kojic acid for different time and then methyl-thiazolyl-tetrazolium assay was performed to evaluate the survival of the cells.ResultsCytotoxic effect for Vero cell with the exposure of kojic acid lower than 750μg/mL for 24 hours incubation was not observed compared with the negative control,but the dose-dependent and time-dependent response was observed after the exposure more than 24 hours.When cells were treated with kojic acid for 48 hours,50% of inhibition effect(IE₅₀)of cell viability appeared at 2 000μg/mL,followed by IE₅₀≤500μg/mL for more than 72 hours treatment.Cultured cells incubated with kojic acid simultaneously for 24 hours resulted in no difference in toxicity.There was a light inhibition in CHO-K1 cells exposed to kojic acid of more than 1 000μg/mL for 24 hours.With elongation of the cell incubation with kojic acid for 48,72 and 96 hours,obvious cytotoxicity to the cells was observed.ConclusionKojic acid has toxic effect on Vero and CHO-KI cell lines with significant dose-and time-response manner.