Gastroparesis syndrome is a recognized complication of longstanding diabetes mellitus and is attributed to reduced gastric contractility due to 'autovagotomy'. However, motor abnormalities associated with this syndrome may not be limited to the stomach. To test this hypothesis we have studied the fasting and fed manometric profiles of the proximal small intestine of fourteen patients with the clinical diagnosis of gastroparesis. Abnormal intestinal manometric patterns were observed in twelve out of the fourteen patients. In four patients there was reduced duodenojejunal phasic pressure activity, whereas in nine there were non-propagated long bursts of powerful contractions. Furthermore, while the majority of patients (eleven out of fourteen) exhibited the expected reduction in antral pressure activity and gastric phase III, a small subgroup of three patients exhibited a peculiar continuous 3 min-1 antral contractile activity. Our findings show that the small intestine is frequently affected in patients with diabetic gastroparesis, and that the motility disorder both in the stomach and the small bowel is not invariably of a 'paretic' type. The occurrence of incoordinated intestinal long bursts and continuous antral activity suggests that disturbed sympathetic innervation participates in the aetiopathogenesis of their upper-gut dysfunction.