The present invention relates to a method for increasing the content of rare ginsenosides in preparing an extract of genus Panax including wild ginseng or ginseng, cambial meristematic cells of genus Panax or an extract thereof, a ginseng extract prepared by the method, cambial meristematic cells (CMCs) of genus Panax or an extract thereof prepared by the method, and to a composition comprising the same. Specifically, the present invention relates to a method for increasing the content of rare ginsenosides such as Rh2, in preparing an extract of genus Panax including wild ginseng or ginseng, cambial meristematic cells of genus Panax or an extract thereof, a ginseng extract prepared by the method, cambial meristematic cells (CMCs) of genus Panax or an extract thereof prepared by the method, and to a composition for improving blood circulation or a composition for improving liver function, which contains, as an active ingredient, a extract of genus Panax, cambial meristematic cells of genus Panax or an extract thereof, prepared by the method.