Abstract Sixty patients were evaluated 10 years after vagotomy for duodenal ulcer. In 31 the stain leucomethylene blue had been used peroperatively to visualize remaining nerve twigs on the distal oesophagus when the surgeon had deemed the vagotomy to be complete and in 29 cases the staining technique was not used. The frequency of recurrent ulcer was not influenced by the use of the staining technique. A series of 48 patients who had a parietal cell vagotomy performed for duodenal ulcer was randomized into staining and control groups. There was no significant difference in the reduction of the preoperative peak acid output after pentagastrin stimulation between the two groups. Only 33 per cent of specimens stained contained nerve tissue. It is concluded that the colouring of the distal oesophagus with leucomethylene blue is of no clinical value in achieving completeness of vagotomy.