Eriocaulon sieboldianum (ES) is used in traditional oriental medicine for various medicinalpurposes including headache, toothache, and inflammation. However, the anti-cancer effect ofthe ES is still not fully understood. In the present study, the human leukemia cell line HL-60 wasused to characterize the apoptotic effects of ES. ES induced cytotoxicity of HL-60 cells in a dose-and time-dependent manner. ES induced the generation of reactive oxygen species, and therelease of cytochrome c in a dose-dependent manner. In addition, we showed that ES-inducedapoptosis was accompanied by activation of caspase-3. Taken together, our results demonstratethat ES possesses anti-cancer activity in HL-60 cells.