AIM: To study the anti-tumor effect of resveratrol and in combination with 5-FU on murine liver cancer.METHODS: Transplantable murine hepatoma22 model was used to evaluate the anti-tumor activity of resveratrol (RES)alone or in combination with 5-FU in vivo. H22 cell cycles were analyzed with flow cytometry.RESULTS: Resveratrol could inhibit the growth of murine hepatoma22, after the mice bearing H22 tumor were treated with 10 mg/kg or 15 mg/kg resveratrol for ten days, and the inhibition rates were 36.3% (n = 10) and 49.3% (n = 9),respectively, which increased obviously compared with that in control group (85±22 vs 68±17, P＜0.01). RES could induce the S phase arrest of H22 cells, and increase the persentage of cells in S phase from 59.1% (n = 9) to 73.5% (n = 9) in a dose-dependent manner (P＜0.05). The enhanced inhibition of tumor growth by 5-FU was also observed in hepatoma22 bearing mice when 5-FU was administered in combination with 10 mg/kg resveratrol. The inhibition rates for 20 mg/kg or 10 mg/kg 5-FU in combination with 10 mg/kg resveratrol were 77.4% and 72.4%, respectively, compared with the group of 20 mg/kg or 10 mg/kg 5-FU alone, in which the inhibition rates were 53.4% and 43.8%, respectively (n = 8). There was a statistical significance between the combination group and 5-FU group.CONCLUSION: RES could induce the S phase arrest of H22cells and enhance the anti-tumor effect of 5-FU on murine hepatoma22 and antagonize its toxicity markedly. These results suggest that resveratrol, as a biochemical modulator to enhance the therapeutic effects of 5-FU, may be potentially useful in cancer chemotherapy.