Active principles for the anti-fatigue activity of Panax ginseng were studied in mice using the swimming performance method. Ginseng water extract maximized the prolongation of swimming time 18 hours after administration. The potencies of anti-fatigue activities were found as in the order of ether soluble fraction and butanol soluble fraction as those of antioxidant activities previously determined. The anti-oxidant components, maltol, salicylic acid and vanillic acid isolated from the ether soluble fraction of Panax ginseng strongly exhibited the antifatigue activities, where as highly purified crystalline ginsenoside $4Rb_1$, Re and $4Rg_1$ did not.