The effect of metoclopramide (20 mg p.o) on the times taken for a radiolabelled liquid starch meal to empty from the stomach and to reach the ileum (230 cm from the mouth), the ileal flow rates and the degree of carbohydrate absorption were studied in five normal male volunteers, intubated with a four lumen intestinal tube. Administration of metoclopramide significantly reduced the time taken for delivery of 50% and 80% of the meal to the ileal aspiration site, but had no significant effect on the half time for gastric emptying. Administration of metoclopramide did not affect the average flow rate or the total postprandial volume, which passed the ileal aspiration site. Administration of metoclopramide reduced carbohydrate absorption in every subject by between 8 and 30%. This study is consistent with the hypothesis that metoclopramide may reduce the degree of absorption in the human small intestine by decreasing the contact time between food and small intestinal epithelium, though it could also act by reducing the area of mucosa in contact with nutrients.