Conventional oesophageal manometry is seldom accompanied by symptoms and may indeed be normal in patients with a history of dysphagia. We have recently shown that oesophageal manometry during eating may be helpful in the evaluation of patients with dysphagia but there has been little systematic comparison of fed oesophageal motor patterns with conventional clinical manometry. Oesophageal manometry in response to water swallows and during eating was therefore examined in 58 consecutive patients who had been referred for clinical oesophageal function studies. The patients were divided into three groups according to the percentage of peristaltic activity during conventional manometry: group 1 (n = 21) had 100% peristalsis; group 2 (n = 29) had 1-99% peristalsis and group 3 (n = 8) were aperistaltic. All the patients in group 3 had achalasia and remained aperistaltic during eating, however, was less than with water swallows in both group 1 (53% compared with 100%) and group 2 (49% compared with 82.3%) patients. Synchronous contractions and non-conducted swallows were correspondingly increased during eating. Although there was a significant correlation between the amplitude of peristaltic contractions with water and bread in groups 1 and 2, mean peristaltic amplitudes were less with bread than with water swallows. The data show that there are substantial differences in the distal oesophageal motility patterns produced by water swallows and by eating. Conventional manometry with water swallows does not allow prediction of the fed oesophageal motility pattern, except in patients with achalasia.