This study was undertaken to determine if men and women have similar rates of gastric emptying. Fifteen normal weight male subjects aged 20-53 yr (mean 30 yr) and 15 normal weight female subjects aged 20-45 yr (mean 32 yr) were studied. Each subject ingested an identical 300-g meal consisting of 150 g of beef stew and 150 g of orange juice. Technetium-99m-(99mTc) labeled liver pate was used as the radioactive marker for the solid phase; indium-111 DTPA [( 111In]DTPA) was the liquid marker. A scintillation camera and computer was used to measure the rate of emptying of the solid and liquid phases. Correction for radionuclide depth, decay, and crosstalk was performed. The half-emptying time for men was: solids 59.8 +/- 3.7 min, liquids 30.3 +/- 2.3 min, and for women was: solids 92.4 +/- 7.5 min, liquids 53.8 +/- 4.9 min. These differences were statistically significant (solids, p = 0.00097; liquids, p = 0.00038). We conclude that women empty both solids and liquids from their stomachs more slowly than men. Possible mechanisms for the difference in gastric emptying rates between men and women are discussed.