The use of scolocidal solutions in the hepatobiliary system may result in caustic sclerosing cholangitis. In this study, the effectivenes of a biological metabolite of albendazole, albendazole sulfoxide, on scolices and the hepatobiliary system was evaluated. In the in vitro study, it was found that 100 mu g/ml albendazole sulfoxide solution had strong scolocidal effect in 15 min. In the in vivo study, two experimental groups, each consisting of 8 rabbits aged 3-4 months and weighing 2,500 +/- 250 g, 100 mu g/ml albendazole sulfoxide and normal saline were given into the biliary tract. ALP, GGT, SGOT and SGPT values on days 7, 30 and 60 were not found to be significantly increased compared to preoperative values. Total bilirubin values were high in the working group 7 and 30 days postoperatively and on day 30 in the control group, returning back to normal levels on day 60 in both groups. Histopathological evaluation of the liver parenchyma and the biliary system on day 60 revealed no differences between the groups. Consequently, albendazole sulfoxide solution may be used intraoperatively for scolocidal purposes.