During investigation of the anthelmintic substances against Clonorchis sinensis which are based on the structure of meso-dihydroguairaretic acid, some non-mesoic diaryl butanes were synthesized by Grignard reaction and their anthelmintic activities were determined. In this reaction, an aryl butanone was reacted with benzylmagnesium chloride to produce the corresponding diaryl hydroxybutane which was converted to the corresponding diaryl butane by zinc and hydrogen chloride. The substituents in benzene ring of the diaryl butanes were changed by methylation or demethylation. Among the synthesized substances, 4-phenyl-1-(3, 4-dihydroxyphenyl)-2, 3-dimethylbutane(VII), 4-phenyl-1-(3-hydroxy-4-methoxyphenyl)-2, 3-dimethylbutane(IX) and 4-phenyl-1-(4-hydroxy-3-methoxyphenyl)-2, 3-dimethylbutane(VI) showed strong wormicidal effects against Clonorchis si-nensis in that order. Phenolic hydroxyl group seemed to play a certain role for the wormicidal activity of the diaryl butanes.