Abstract: Four antimonial compounds were prepared. Dichloro-(α-carbomethoxyphenyl) -thio- antimonite and dichloro- (α-carbethoxyphenyl)thioantimoni were prepared by the action of antimony trichloride on methyl and ethyl esters of thiosalicylic acid respectively. 2-Methyl-1,3-benzimidazole and 2-mercapto-benzothiazole were heated with antimony trichloride in benzene. Two corresponding antimonial compounds were obtained. The structure of these tWo compounds have not been determined as yet. These four compounds were tested for therapeutic effect on schistosomiasis japonica in mice and was compared with tartar emetic. It was found that they had higher effec- tiveness than tartar emetic when higher dosages (by weight) were used.