Gentiana uchiyamana Nakai is a perennial herb in Gentianaceous plants. From the root of Gentiana uchiyamana Nakai, the bitter secoiridoid glucosides were isolated and identified as gentiopicroside and swertiamarin. A high-performance liquid chromatographic method for quantitative determination of bitter component, i.e. gentiopicroside in the roots of Gentiana scabra and G. uchiyamana Nakai was developed, using a ${mu}$-Bondapak $C_{18}$ column and methanol-water mobile phases. The content of gentiopicroside was calculated from calibration curve previously prepared using the standard, 3.55% in the roots of Gentiana scabra and 1.58% in Gentiana uchiyamana Nakai.