Objective To determine the glutathione (GSH) content in a human hepatoma cell line (SMMC-7221) treated with xylitol/selenite, providing a part of an investigation of its anti-cancer mechanisms. Results The nuclei of SMMC-7221 cells were stained with Hoechst 33258 in an apoptosis assay, and their morphology subsequently changed from circular to crescent shape. The calibration curve (r(2) = 0.992) was established, and GSH content markedly decreased after treated with 0.5 and 1 mg xylitol/selenite l(-1) for 12, 36 and 60 h (12 h: from 95.57 +/- A 19.57 to 29.09 +/- A 7.74 and 24.27 +/- A 11.15; 36 h: from 70.73 +/- A 11.35 to 19.54 +/- A 6.39 and 9.35 +/- A 6.69; 60 h: from 72.63 +/- A 16.94 to 7.432 +/- A 3.84 and 0). The depletion rate of GSH was more related to the concentration of xylitol/selenite than the treatment time (from 69.95 +/- A 1.87 to 100 % vs. 0.22 +/- A 0.2 to 100 %). Conclusions Xylitol/selenite is a promising anti-cancer drug to induce apoptosis in SMMC-7221 cells. It may regulate the apoptosis through the co-action of multiple mechanisms related to GSH depletion.