Abstract: This paper comments on the severity of side effects of pyquiton on the liver functions of the patients. The paper analysed the results of 664 cases of schistosomiasis japonica of various types, all treated by pyquiton during 1978-1981 and concluded that the liver damage produced by pyquiton in ordinary dosage was rare and mild. Cases with impaired liver function after the treatment of pyquiton were observed in only 2.29% of those with normal liver functions before treatment. 81.4 % of those with abnormal function before treatment or complicated with other liver diseases tolerated pyquiton well, while in -4.3% there were some aggravations of abnormal liver functions; but the damage was recovered rapidly under accessory hepatic treatment.The authors' data suggest that pyquiton is superior to other classical schistosomicides in causing little hepatic damage, so it can be used in schistosomiasis cases complicated with liver diseases.