The objective of this study is to quantify the puerarin in rat plasma following oral administration of TZ18 and compare the pharmacokinetics characteristics of puerarin in normal rats with that in depression model rats. A high performance liquid chromatography method was used to quantify the puerarin due to its good selectivity and linearity (coefficient correlation, r2 = 0.9991) within the tested range (0.028-0.889 μg·mL-1). Intra- and inter-day precision coefficients of variation and accuracy bias were acceptable (Maximum coeffi- cient of variation was 5.74% for intra-day and 3.09% for inter-day) over the entire range. The recoveries were found to be 98.3%, 101.4%, and 103.4% for concentrations of 0.028, 0.222, and 0.444 μg·mL-1, re- spectively. The concentration-time curves for both normal rats and depression model rats were fit to a two- compartment model with the first order absorption. The results show significant differences in the main phar- macokinetic parameters of peak time, peak concentration, and the area under the concentration-time curve between the two kinds of rats. The objective of this study is to quantify the puerarin in rat plasma following oral administration of TZ18 and compare the pharmacokinetics characteristics of puerarin in normal rats with that in depression model rats. A high performance liquid chromatography method was used to quantify the puerarin due to its Good selectivity and linearity (coefficient correlation, r2 = 0.9991) within the tested range (0.028-0.889 μg·mL-1). Intra- and inter-day precision coefficients of variation and accuracy bias were acceptable (Maximum coeffi- cient of variation was 5.74% for intra-day and 3.09% for inter-day) over the entire range. The recoveries were found to be 98.3%, 101.4%, and 103.4% for concentrations of 0.028, 0.222, and 0.444 μg·mL-1, re The results show significant differences in the main phar-macokinetic parameters of peak t - spectively. The concentration-time curves for both normal rats and depression model rats were fit to a two- compartment model with the first order absorption Ime, peak concentration, and the area under the concentration-time curve between the two kinds of rats.