Objective: To study the mechanism of inhibitory effect of ginsenoside Rg3 on tumor growth. Methods: The chick chorioallantoic membrane(CAM) test and Lewis lung carcinoma model were used to investigate the inhibitory effect of Rg3 on tumor angiogenesis. Results: Rg3(0.1 or 0.5 mmol/L) obviously inhibited angiogenesis in the CAM. Treatment with Rg3 in vivo obviously inhibited Lewis lung carcinoma growth with the inhibition ratio from 23% to about 47%. We also observed that the angiogenesis in implanted L...