From 1979 to 1984, 141 consecutive patients (110 men, 31 women) underwent highly selective vagotomy (HSV) for duodenal ulcer (DU). All patients had received pre-operative treatment with full dose H2 receptor antagonists (H2RA). Indications for surgery were: persistent relapse on withdrawal of H2RA, 107 (75.9 per cent); no response to H2RA, 30 (21.3 per cent); intolerance of H2RA, 1 (0.7 per cent); acute DU bleed, 2 (1.4 per cent); duodenal stenosis, 1 (0.7 per cent). Follow-up with a median of 47 months (24-85 months) revealed six patients (4.4 per cent) with endoscopically proven recurrence, three of whom were on non-steroidal anti-inflammatory drugs (NSAIDs). Only one patient with recurrent DU was a non-responder to H2RA pre-operatively. Twenty-five patients remained symptomatic after HSV without ulcer recurrence, of which a highly significant proportion (41 per cent) were non-responders (P less than 0.001). The pre-operative response to H2RA does not indicate the likelihood of ulcer recurrence after HSV. However, non-responders are more likely to continue with dyspeptic symptoms despite the successful healing of their ulcers. The DU recurrence rate in patients taking long-term NSAIDs is disappointingly high (33 per cent), putting the use of HSV in these patients into question.