Objective: To assess the effect of metoclopramide on gastric motility in critically ill patients. Design: Prospective, controlled, single-blind cross-over trial. Setting: A 10-bed general intensive care unit. Patients: Ten critically ill, enterally fed adult patients without renal failure. Interventions: Each patient received enteral feeding with Enrich via a nasogastric tube at 50 ml/h throughout the 5-h study period on two consecutive days. Either normal saline (control) or 10 mg of metoclopramide (treatment) was administered intravenously at the start of the study period in random order with cross-over design. Measurements and results: Gastric motility was measured indirectly by analysis of the absorption over time of 1.5 g of paracetamol administered into the stomach at the start of the study period together with a 100 ml bolus of Enrich feed. The rate of gastric emptying is proportional to the area under the line plot of serum paracetamol concentration against time over 120 min (AUC120). Eight of the ten patients studied showed an increased AUC120 with metoclopramide compared to that with saline. Statistical analysis with the Wilcoxon signed rank test gave a p value of 0.04, indicating a significant increase in gastric emptying following administration of metoclopramide. Conclusions: The administration of intravenous metoclopramide improved gastric emptying in a heterogeneous group of critically ill patients. Metoclopramide is a useful prokinetic drug in this patient population.