Abstract A retrospective analysis of 48 patients undergoing mono-octanoin infusion via nasobiliary catheter following failure of endoscopic extraction of common bile duct stones is reported. Among 35 patients who received a complete course of treatment, nine (26 per cent) had duct clearance by the completion of the infusion and a further eight on subsequent endoscopic retrograde cholangiopancreatography (ERCP) (total 49 per cent). Two patients had a successful stone extraction after enlargement of the sphincterotomy (total non-surgical clearance rate 54 per cent). None of the patients with stones > 2 cm in diameter had stone clearance at the completion of the infusion and only one at subsequent ERCP. Among 13 patients receiving an incomplete course of treatment seven had clear ducts on repeat ERCP (54 per cent). Mono-octanoin infusion via a nasobiliary catheter is of limited value in the management of this difficult group of patients, although it may be successful in some.