AIM Investigation of the synergetic effect of paclitaxel and an ent-kaurene diterpenoid compound in human gastric cancer cell line MGC 803.METHODS Cell proliferation was determined by MTT assay.Western blot were performed to monitor the expression change of Bax, Bcl-2 and p53.For in vivo study, human gastric cancer cell line MGC 803 were injected into nude mice as xenograft tumor models, and the tumor weights were measured after treatment with paclitaxel, the compound or combined together for 21 d to evaluate the in vivo inhibition rate.RESULTS For in vitro study, the result of MTT assay showed that the cell growth was significantly inhibited when they were synergistically used in quite small dose (inhibition rate < 25%) and the expression of Bax and p53 were significantly increased in the synergetic treatment, whereas the expression of Bcl-2 was decreased.In the synergetic group,the inhibition rate (90.0%) which is evaluated by tumor weights is much higher than that of paclitaxel (72.4%) and the compound (11.7%).CONCLUSION Synergetic use of paclitaxel and the ent-kaurene diterpenoid compound may be a promising method for the treatment of gastric cancer.Meanwhile the side effects of paclitaxel can be minimized in the synergetic treatment.