Changes in volume of muscular oxygen consumption and content of lactate concentration and activity of lactate dehydrogenase were determined in rats that had been injected ginseng (20mg/Kg/day) for 10 days and another group had been injected nothing. Both groups had been performed exhausting exercise of running treadmill (3.6 Km/hr) for 1 hr. The oxygen consumption in muscle were measured by Warburg method, and lactate content in muscle were measured by Braker and Summerson method and activity of lactate dehydrogenase were measured by Cabaud and Wroblewski method. 1. Content of lactate In control group and ginseng group, the lactate concentration were 51.44±14.00 (M±S.D.)mg% and 31.06±10.48(M±S.D.)mg% respectively. 2. Activity of lactic dehydrogenase In control group and ginseng group, the activity of lactic dehydrogenase were 716.07±76.88 (M±S.D.) Unit/ml and 687.27±124.26(M±S.D.) Unit/ml respectively. 3. O₂ Consumption In control group and ginseng group, the O₂ consumption in muscle tissue were 1.00±0.24 (M±S.D.) u10₂/mg.hr. and 1.12±0.31 (M±S.D.)u10₂ /mg.hr. respectively.