Seventeen patients with bile duct calculi were treated alternately with a preparation of glycerol octanoate and a bile salt-EDTA solution via a nasobiliary tube. Of 14 patients (group I), it was necessary to operate on four immediately after irrigation therapy, success resulted from this conservative therapy in eight (57%) cases and two were unchanged. Laboratory investigations showed a decrease in zinc and copper concentrations in the serum. Of the patients 50-60% suffered from vomiting and diarrhea. For three patients (group II), there was an interval of 6-26 days between the end of the therapy and operation. Histological findings in the patients in group I and II subjected to operation included acute ulcerative and chronic inflammation in gallbladder and common bile duct walls. Since the alterations were of minor degree in four of the seven patients who subsequently underwent surgery the risk of irrigation therapy seems to be acceptable.