The wormicidal effect on Clonorchis sinensis in boiled water extracts of 223 species (vegetable origin 206, animal origin 10, mineral origin 7) of raw drugs prescribed in Oriental medicine was observed in vitro. The wormicidal substances were detected from 31 of the above-mentioned species. The wormicidal substances extracted from Platycodon grandiflorum (radix), Schizandra chinensis (fruit), Polygala tenuifolia (herb) and Aster tataricus (radix) were most effective. Those from Smilax glabra (radix), Pueraria thunbergiana (flower, radix), Polygala tenuifolia (radix), Scutellaria baicalensis (radix), Prunus mume (fruit), Glycyrrhiza uralensis (radix), Angelica koreana (radix), Phytolacca esculenta (radix) and Cyrtomium fortunei (rhizoma) were effective. The rest of the raw drugs were less effective.