Abstract: To confirm the most appropriate pharmaceutical source and harvest time and provide a scientific basis for exploiting Rumex gmelini, we used HPLC to examine the dynamic distribution of 7 components (resveratrol, polydatin, chrysophanol, chrysophaein, emodin, physcion and musizin) in organs, tissues and development stages of 1- or 2-year-old Rumex gmelini. The kind and content of active components varied in roots as compared with other plant parts, with roots being the most appropriate pharmaceutical source. Musizin was not found in 1-year-old plants. All 7 active components were found in roots of 2-year-old plants, and the content was higher during August and September, so this period is the most appropriate harvest time for R. gmelini.