Abstract: AimTo establish an optimal HPLC method for the determination of the (E)- and (Z)-diastereomers of resveratrol and resveratrol glucoside from the roots of Polygonum cuspidatum. Methods The determination was conducted by using reversed-phase high liquid chromatography. Nucleodur 100-5 C₁₈ column (250 mm×4.6 mm ID, 5 μm), and a mobile phase program of gradient elution with iso-propyl alcohol and water at a flow rate of 0.6 mL·min^-1was employed. The fluorescence detection wavelengths were: λ_ex 334 nm, λ_em 404 nm. ResultsA good linear relationship was obtained under the optimum condition. The average recoveries were 96.7%, 99.1% for the (E)-diastereomers of resveratrol and resveratrol glucoside, 91.1%, 93.7% for the (Z)-diastereomers of resveratrol and resveratrol glucoside, respectively. The RSD of E-resveratrol and its glucoside were 1.34% and 0.72%, respectively. The RSD of Z-resveratrol and its glucoside were 1.27% and 2.08%, respectively. ConclusionThis method is accurate and reliable for the quantity analysis of the (E)- and (Z)-diastereomers of resveratrol and resveratrol glucoside in the roots of Polygonum cuspidatum.