Objectives: Cynanchi wilfordii Radix has commonly been used with or instead of Polygoni multiflori Radix in Korea. The purpose of this study was to investigate their history in the traditional Oriental medical literature and quantitative determination of conduritol F from Cynanchi wilfordii Radix according to various harvest times. Methods: We conducted studies of the traditional Oriental medical literature and analysis of the component, conduritol F, simultaneously. Efficacy and origin of Cynanchi wilfordii Radix in literature study, time of harvest in component research. Chromatographic analysis performed using Silica(2) 100A column (Phenomenex 5 um, 250 mm 4.6 mm) with a mixture of acetonitrile and water (98 : 2)(v/v). The analyses detected at UV (210 nm). Results: Conduritol F was detected in Cynanchi wilfordii Radix, but in Cynanchi auriculati Radix was not. We indicate that conduritol F is as a distinguishable indicator with other materia medica. We think the proper harvesting time is October and November. Conclusions: Measures of trunk control were significantly related with values of dynamic balance and gait. Based on these results, trunk control is an essential core component of balance and gait. Trunk control training programs after stroke should be developed and emphasized.