On the purpose of development of novel antioxidative compounds from natural sources, 38 plants expected to show antioxidant activity have been examined concerning DPPH radical scavenging activity. Among them, thirteen plants, including Paeoniae radix, the root of Paeonia lactiflora, exhibited the activity. In order to isolate active component, the root was extracted in 80% aqueous MeOH and solvent fractionated with EtOAc, n-BuOH and water, successively. Silica gel column chromatographies of the EtOAc and n-BuOH fraction exhibiting antioxidant activity. were repeatedly carried out with monitoring by DPPH assay to afford three active compounds. On the basis of spectral data and the chemical characteristics, the structures of the compounds were determined as (+)-catechin, 1,2,3,4-tetragalloyl-6-digalloyl-β-D-glucose and 1,2,3,4,6-penta-galloyl-β-D-glucose.