In East-South Asia it has been widely known that Korean ginseng(Panax ginseng) increases body temperature, whereas American ginseng(Panax quinquefolius) decreases it. This study was designed to find out if Korean ginseng could increase body temperature comparing with American ginseng. Double-blind randomized controlled trials on body temperature of Korean ginseng and American ginseng in Koreans and Chineses was performed by using electronic thermometer at the ear. There was no significant difference between Korean ginseng and American ginseng in Koreans as well as Chineses by repeated-measures ANOVA. It was revealed that Korean ginseng does not increase body temperature. Maybe the concept that Korean ginseng increase body temperature is concerned with commercial interests dealing with American Ginseng.