To develop the new physiologically active materials from ginseng (Panax ginseng C.A. Meyer) leaves, the ginsenoside-rich fraction (GL-1) was isolated and transformed into highly absorbable metabolites in the gastrointestinal (GI) tract. To transform the ginsenosides in GL-1 into deglycosylated ginsenosides, GL-1 was treated with organic acids (0.1 and 1% lactic and acetic acid solutions) and fermented with isolated strains (P1-P4, and M3) from red ginseng extract for 7 days. The treatment of 0.1% lactic acid of GL-1 induced the highest transforms of partially-deglycosylated ginsenosides such as Mc, F2, and Rg3 (intermediate metabolites). On the other hand, Compound K (Compd K, final metabolite) contents in GL-1 ferments with strain M3 showed about 6-time higher than that of control (not fermented). Consequently, the strain M3 was finally selected for the mass production of Compd K with well-absorbable property in GI tract and physiological activity.