Gastric emptying was measured in 50 young healthy subjects by means of sequential scintigraphy with two radioactive markers. Gastric emptying of the solid component of the meal was slower than that of the liquid component, corresponding to a linear model (T 1/2, 112 min). Gastric emptying of the liquid component was different, following an exponential model, although only after 45 min (100% of the liquid marker retained in the stomach after 15 min, 56.7% after 45 min, 43.3% after 75 min, and 35.5% after 105 min). Significant differences were found in gastric emptying of both solids and liquids among sexes; women emptied the stomach more slowly than men regardless of age, weight, height, or body surface. A relationship was found between gastric emptying and the phase of the menstrual cycle. Furthermore, a quicker emptying of the liquid component was observed in smokers. These factors should be considered in the evaluation of gastric emptying studies.