The technique of gamma scintigraphy has been used to follow the transit of a solution and a pellet formulation in the gastrointestinal tract of healthy volunteers. The emptying of the formulations from the stomach and their arrival at the caecum could be quantified, thereby allowing calculation of transit times for the small intestine. Gastric emptying was affected by the nature of the formulation, i.e. liquid or solid. However, transit through the small intestine was independent of the nature of the administered material.