The aim of this study was to define better the motor phenomena associated with the slowing of gastric emptying by a duodenal lipid infusion. Antral, pyloric and duodenal motility were recorded in 10 healthy subjects with a manometric assembly which incorporated multiple perfused side-holes and a sleeve sensor positioned astride the pylorus. The gastric emptying of a standard solid meal and the distribution of the ingesta between the proximal and distal stomach were monitored with a radionuclide technique. A triglyceride emulsion was infused into the duodenum for 45 min once 25% of the meal had emptied. The infusion caused significant slowing in the rate of gastric emptying (P less than 0.01). This slowing in gastric emptying was associated with the suppression of pressure waves in the distal antrum (P less than 0.01) and proximal duodenum (P less than 0.01), the induction of pressure waves isolated to a narrow pyloric segment (P less than 0.01), and a redistribution of ingesta from the distal to proximal stomach. These findings suggest that pressure waves isolated to the pylorus, changes in the intragastric distribution of ingested food, and changes in proximal duodenal motility may all act in concert with changes in antral motility to regulate the gastric emptying of solids.