To study the pharmacokinetics of ginsenosides Rg1 and its metabolites after iv and oral administration in Wistar rats, the LC-MS/MS method was selected to determine ginsenosides Rg1 and its metabolites in plasma and their pharmacokinetic parameters were calculated. After oral administration of ginsenosides Rg1 to rats, ginsenosides Rg1, Rh1, F1 and protopanaxatriol (Ppt) could be detected in plasma. Their Tmax were 0.92, 3.64, 5.17, and 7.30 h, respectively; MRT were 2.68, 5.06, 6.65, and 5.33 h, respectively; AUC(o-t), were 2 363.5, 4 185.5, 3 774.3, and 396.2 ng x mL(-1) x h, respectively. After iv administration of ginsenosides Rg1 to rats, ginsenosides Rg1, Rh1 and FI could be detected in plasma. Their T1/2betaS were 3.12, 5.87, and 6.87 h, respectively; MRTs were 1.92, 5.99, and 7.13 h, respectively; AUCo-tS were 1 454.7, 597.5, and 805.6 ng x mL(-1) x h, respectively. So, it can be concluded that after oral administration, the amounts of metabolites were higher than the prototype in vivo, and the distribution and elimination of the metabolites were relatively slow. After iv administration, the amount of prototype were higher than that of the metabolites in vivo, and the distribution and elimination of the metabolites were relatively slow.