NOVELTY - Polygonum cuspidatum is crushed, extracted using organic solvent, filtered, and concentrated to obtain crude extract. Crude extract is partitioned between petroleum ether-ethyl acetate-methanol-water, and organic phases and aqueous phases are separated. Organic and aqueous phases are concentrated to obtain samples (1 and 2). Sample (1) is chromatographically separated. Chromatogram of target component fraction is collected and solvent is evaporated. Each component of target fraction is concentrated, dissolved in methanol, and purified to obtain emodin and physcion.    USE - Extraction and purification of emodin and physcion (claimed).    ADVANTAGE - The method efficiently and economically provides high-purity emodin and physcion, without affecting the environment.    DETAILED DESCRIPTION - P.cuspidatum is crushed, extracted using an organic solvent, filtered, and concentrated under reduced pressure to obtain crude extract. The obtained crude extract is partitioned between petroleum ether-ethyl acetate-methanol-water in the volume ratio of 2:5:6:10 and organic phases and aqueous phases are separated. The organic and aqueous phases are concentrated under reduced pressure to obtain samples (1 and 2). The obtained sample (1) is subjected to high-performance liquid chromatography using C18 column with dimension of 250 mmx 4.6 mmx 5 mu m in presence of mobile phase containing methanol and water in the volume ratio of 90:10, in the flow rate of 1 mL/min at room temperature in the detection wavelength of 254 nm. The resultant crude extract is subjected to semi-preparative high-performance liquid chromatography using C18 column under same conditions. The chromatogram of target component fraction is collected manually and solvent is evaporated under reduced pressure. Each component of target fraction is concentrated under reduced pressure, dissolved in methanol, and purified by high-performance liquid chromatography to obtain emodin and physcion with purity of more than 98%.