This investigation was carried out to study the influence of pH and heat treatment on the ginsenosides in the white ginseng extract. Changes in ginsenosides (Rb1, Rb2, ,Rc, Rd) and free sugar were measured by the peak area variation of HPLC chromatogram during 25 hours heat treatment at the various level of pH. It was found that :(1) The peak areas of Rb1. Rb2, Rc and Rd on the HPLC chromatogram were decreased remarkably below pH 4.0 and more decrease was found as the temperature and heating time increased. (2) Those of glucose and arabinose were increased remarkably. It is considrered that the increase of glucose and the formation of arabinose result from the hydrolysis of ginsenoside( Rb1, Rb2, Rc, Rd) linked with sugars.