Using ³H-ginsenosides Rbl, Re, and Rgl, gastrointestinal absorption, organ distribution, excretion, protein binding, and subcellular distribution of them were studied. The results are summarized as following; 1) The absorptions of ³H-ginsenosides in the gastro-intestinal tract of mice showed individual variation between 10-5096. Higher dosage of ³H-ginsenosides above the pharmacological dosage seems to reduce the absorption rate. 2) After oral administration, all ³H-ginsenosides were markedly decomposed in GI tract, but major component excreted through urine was found to be the intact ginsenosides. The total amount of excreted radioactivity during 26 h was only 1-2% of the administered dose. 3) Although the absorption rates are markedly affected by the change in the dosage, the retention in tissue seems to give roughly a constant value around 2.2 × 10-6 molar concentration as the ginsenosides Rx bases in lung. 4) ³H-ginsenosides were distributed mainly in lung, kidney, and liver but only a trace amount in brain. 5) In subcellular distribution experiments, ³H-ginsenosides Rbt was not found in the mitochondrial fraction. 6) On the equilibrium dialysis experiments, ³H-ginsenosides Rb₁ showed a strong binding affinity with the high molecular membrane fractions of organ homogenates and with serum proteins, but ³H-ginsenosides Re and Rg₁ showed very weak binding to the same fractions.