OBJECTIVE: To study the effect of ginsenoside on apoptosis of human leukemia-60 (HL-60) cells and its mechanism. METHODS: MTT cytotoxicity assay was used to determine the growth inhibition activity of ginsenoside (100, 50, 25, 12.5, 6.25, 3.125 and 1.5625 μmol/L) on HL-60 cells. The apoptosis of HL-60 cells after treatment with ginsenoside (0,5,10 and 20 μmol/L) was determined by Annexin V-FITC/PI staining and flow cytometry. The cleavage of total proteins by caspase-8, caspase-9 and caspase-3 was evaluated by Western blot. The cleavage of caspase-3 protein was detected by Western blot after treatment with 10 μmol/L ginsenoside and caspase-8 and 9 inhibitors. RESULTS: Ginsenoside had potent cytotoxicity on HL-60 cells, with an IC50 value of 7.3±1.2 μmol/L. After treatment with ginsenoside (0, 5, 10 and 20 μmol/L) for 48 hours, the apoptotic rate displayed a dose dependency, as shown by flow cytometry, with significant differences between the groups (F=12.67, P<0.01). Western blot showed that there were caspase-9 and caspase-3 cleavage bands, but without caspase-8 cleavage band. The specific inhibitor of caspase-9 Z-LEHD-FMK could block the caspase-3 cleavage induced by 10 μmol/L ginsenoside, but the specific inhibitor of caspase-8 Z-IETD-FMK did not have this effect. CONCLUSIONS: Ginsenoside can induce apoptosis of HL-60 cells, which may be related to a mitochondria-dependent pathway.