The elimination, distribution, excretion of magnesium glycyrrhizinate (MG) after intravenous (i.v.) administration in rats, and the binding rate of MG to plasma protein were investigated. The concentrations of MG in plasma, tissue, and excretion of rats after i.v. administration of MG were measured using reversed-phase high performance liquid chromatography (RP-HPLC). The concentrations of MG in plasma declined in an apparent biexponential manner. The pharmacokinetic parameters from a two-compartment model analysis of plasma samples after i.v. administration of MG 30, 60, and 120 mg/kg-, were t(1/2beta) (min): 140, 180, and 240; AUC(0 approximately 18) (g x min x L(-1)): 10212, 15432, and 50321; CL (L x kg(-1) x min(-1)): 0.0025, 0.0039, and 0.0021, respectively. The drug administered as an iv injection, were mainly cumulated in the liver. When MG was administered to bile-duct cannulated rats, about 90% of i.v. dosed MG was excreted into bile under unchanged form within 24 h after administration. The average binding rate of MG to plasma protein was 87%. The experimental results showed that the distributional property of MG in the present rats study is beneficial to its liver protective activity and liver function improvement.