Ginseng is prepared from Panax ginseng C.A. Meyer root. The root of wild P. ginseng has long tortuous rhizome called traditionally "Rozu" in Japanese. In the present historical studies on ginseng, it has been proven that ginseng has sometimes been used after removing "Rozu" due to its emetic effects. However, ginseng with "Rozu" is prescribed in almost all the present Kampo formulations used clinically in China and Japan. Possible reasons for this are (1) some formulations including "Rozu" have been used for vomiting resulting from the retention of fluid in the intestine and stomach, "tan-in" in Japanese, and (2) the present cultivated ginseng has shorter "Rozu" than wild ginseng. Furthermore, it is proved that "Rozu", rich in ginsenoside Ro with oleanane-type aglycone, is distinguished from ginseng roots rich in ginsenosides Rb1 and Rg1 with dammarane-type aglycone. This is the first report to declare the distribution of ginsenosides in underground parts of wild P. ginseng. Ginsenoside Ro is a minor ginsenoside in ginseng whereas it is the major ginsenoside in P. japonicus rhizome (chikusetsu-ninjin in Japanese). Ginsenoside Ro is characterized by antiinflammatory effects which differ from ginsenosides Rb1 and Rg1 responsible for adaptogenic effects of ginseng. These results suggest that "Rozu" containing both oleanane- and dammarane-type ginsenosides might be a promising raw material distinct from ginseng root or P. japonicus rhizome.