To verify allelopathic effects of Artemisia princeps var. orientalis, a number of laboratory experiments have been performed. Aqueous extracts of leaves, stems and roots of the above species inhibited the seed germination and seedling growth of experimental species, receptor plants. In general, the higher was the concentration of the extracts, the lower was the germination and the growth ratio. Volatile substances released from leaves of the donor plants also inhibited the seed germination and the radicle elongation of receptor plants. Therefore, to find out the inhibitory substances emitted from the wormwood, gas chromatography was employed. As a result of the analysis, 17 KDICical substances were isolated from the leaves and most of them were identified as phenolic compounds.