• The possibility that stones in the common bile duct may disappear during conservative treatment with 3 to 4 Gm. of bile salts per day by mouth is illustrated by the histories of nine patients selected from a larger series of patients who have undergone cholecystectomy and choledochostomy with insertion of a T-tube in the common duct. The nine patients constituted a group in whom postoperative cholangiography gave evidence of retained or recurrent stones and in whom obstruction of bile flow was incomplete so that the T-tube could be clamped all the time. In seven of these patients, the "stone" shadows vanished in 8 to 13 weeks. In two, the shadows persisted, and stones were removed at a subsequent operation. Proof that the shadows represented stones and that the administration of bile salts played a decisive part in their disappearance was not absolute, and the question whether the stones disintegrated, dissolved, or passed unchanged was not settled, but significant evidence relating to these problems was obtained.