Patients with the irritable bowel syndrome (IBS) often have symptoms from both proximal and distal parts of the gut. Motility disturbances have been reported to occur from the esophagus to the distal colon in IBS patients. The patients often have a decreased lower esophageal sphincter pressure and various abnormalities of esophageal peristalsis. Mean transit time in the small intestine after a meal is short in patients with diarrhoea, and long in patients with constipation and pain compared with normals. IBS patients also show abnormalities of the interdigestive MMC, particularly when exposed to stressful stimuli. Previous studies of the colonic oscillating control potential suggested an increased prevalence of 3/min. slow waves in IBS patients compared with normals, but later studies could not confirm this. Long time measurements with multiple electrodes along the colon show a high prevalence of short-lasting segmental contractions in constipated patients, while both short and long-lasting contractions are decreased in painless diarrhoea. Rectal recordings in IBS patients have shown an increased contractile response up to 3 hrs after a meal. --The disturbed gut motility in IBS patients seems to be due no neural influences rather than strictly myogenic factors.