Panax ginseng C. A. Meyer has been one of the most highly recognized medicinal herbs in the Orient. Previous experiments have demonstrated that $Rg_3,\;and\;Rg_5$ statistically significantly decreased the incidence of benzo(a)pyrene-induced mouse lung tumor, $Rh_2$ showed tendency of decrease and $Rh_1$ showed no effect. It was, therefore, concluded that $Rg_3,\;Rg_5\;and\;Rh_2$ are active cancer chemopreventive components in red ginseng and they either singularly or synergistically act in the prevention of cancer. This study was undertaken to compare the cancer chemopreventive effects of $Rg_3,\;Rg_5\;and\;Rh_2$(purity: more than $60\%$) isolated from fermented ginseng extract and BST fermented ginseng with fortified ginsenoside $Rg_3\;and\;Rh_2$. The cancer chemopreventive effects were investigated in experimental groups treated with benzo(a)pyrene(BP) with ginsenoside $Rg_3,\;Rg_5\;Rh_2\;or\;BST$ at three doses of $50^{\circ}C/ml,\;100^{\circ}C/ml\;and\;200^{\circ}C/ml$ When mice given with $50^{\circ}C/ml$ concentration of ginsenoside $Rg_3$ combined with BP for 6 weeks after BP administration, $Rg_3\;showed\;60\%$ of lung tumor incidence, where as $100^{\circ}C/ml\;and\;200^{\circ}C/ml\;of\;Rg_3$ combined with BP groups had significant decrease of incidence $(40.0\%)$ respectively, with the inhibition rate being $35.5\%.$ While the tumor incidence was not decreased in the group treated with BP and 50 of $Rg_5,$ the incidence was $34.0\%\;and\;32.0\%$ in the group treated with BP and 100 and 200 of $Rg_5$, respectively. These incidences were significantly less than the group treated with BP alone, with the inhibition rate being $45.2\%\;and\;48.4\%,$ respectively. On the other hand, in the group treated with BP and 50 of ginsenoside $Rh_2,$ the tumor incidence was not decreased. However, the incidence was $40.0\%\;and\;38.8\%$ in the experimental treated with BP and 100 and 200 of $Rh_2,$ respectively, with the inhibition rate being $45.2\%\;and\;48.4\%,$ respectively. In addition, the incidence showed the tendency to decrease in the experimental group treated with BP and 50 of BST which contained $16.2\%\;of\;Rh_2,\;15.4\%\;of\;Rg_3\;and\;2.5%\;of\;Rg_5.$ The tumor incidence was $54.0\%$ in this group. In the group treated with 100 and 200 of EST, the incidence was $34.0\%\;and\;30.0\%,$ respectively, the incidences significantly being lower than the group treated with BP alone, with the inhibiting rate being $45.2\%\;and\;51.6\%,$ respectively. The results of this study strongly suggested that ginsenoside $Rg_3,\;Rg_5\;and\;Rh_2$ are the active components of red ginseng having a cancer chemopreventive activity and $Rg_5$ is the strongest cancer chempopreventive among them. On the other hand, the results demonstrating that the incidence of lung tumor was more markedly reduced by BST fermented ginseng with fortified ginsenoside $Rh_2\;or\;Rg_3$ compared to the single component alone, suggest that the combination of these components may remarkablely improve the cancer preventive effect