Background: The effects of octreotide on small intestinal and gall-bladder motility are well established. However, the influence of octreotide on the gastric emptying rate of both solids and liquids in normal healthy volunteers has never been studied. Methods: In nine healthy subjects, the gastric emptying rate of liquids and solids was studied in basal condition and 30 min after subcutaneous administration of 50 mu g of octreotide, using the combined C-14-octanoic acid/C-13-glycine breath test. To determine if the results were entirely due to alterations in gastric emptying, (CO2)-C-14/13 excretion rates of intraduodenally administered C-14-octanoic acid and C-13-glycine were measured in basal condition and after subcutaneous injection of octreotide. Results: After subcutaneous injection of octreotide, the gastric emptying rate of solids was decreased in all but one subject, while the gastric emptying rate of fluids was decreased in all subjects. Nevertheless, (CO2)-C-14/13 excretion rates in the breath after intraduodenally administered C-14-octanoic acid and C-13-glycine, were similar in basal condition and after subcutaneous injection of octreotide. Conclusions: Subcutaneous injection of a single physiological dose of octreotide induces a marked delay in the gastric emptying of solids and liquids in young healthy volunteers. The combined C-14-octanoic acid/C-13-glycine breath test is very well suited to demonstrate this effect, since the absorption and metabolism of octanoic acid and glycine remains unaltered after administration of octreotide.