Between July and November 1985, we have detected radiologically failure of staple closure after large bowel anastomosis with the Ethicon Proximate ILS Stapler in four patients. Three of the patients had clinical evidence of an anastomotic leakage. The problem, which has also occurred in an experimentally stapled anastomosis, appears to be a recent phenomenon and may be caused by an instrumental failure. Because the staplers are disposable, tracing the possible fault has been difficult. Documentation is recommended in patients' notes of the instrument and the batch numbers of all disposable surgical staplers that are used in operations.