Gastric adaptive relaxation and symptoms after vagotomy. Gastric adaptive relaxation is reported to be impaired after vagotomy. This abnormality has been implicated in the pathogenesis of postvagotomy symptoms, but no association has previously been demonstrated between the two. Gastric adaptive relaxation was measured in 15 healthy volunteers and 33 patients more than 1 year after highly selective vagotomy or truncal vagotomy and drainage. Seventeen patients were asymptomatic. The remainder were symptomatic including seven patients with persistent diarrhoea. Fasted subjects were intubated with a Ryle's tube containing a pressure microtransducer within a flaccid (800 ml) plastic bag. Gastric corpus-fundus pressure was recorded during distension of the bag with air (15 ml/s) over 30 s. Pressure indices were derived from the areas under the pressure curves. Median (range) pressure indices were: healthy volunteers 12.7 (7.5-17.1) cmH2O, highly selective vagotomy 14.0 (9.8-15.9) cmH2O (n.s.), truncal vagotomy and drainage 14.5 (8.6-26.8) cmH2O (P = 0.04). All patients with diarrhoea had abnormally high pressure indices (P less than 0.001). Pressure indices in all other patient groups were within the normal range. We conclude that gastric adaptive relaxation remains abnormal in patients with postvagotomy diarrhoea but not in those who are asymptomatic or who have other symptoms. 