A gamma camera coupled to a computer was used in 20 normal volunteers after ingestion of the mixture of Tc-99m-DTPA and milk in order to determine gastric emptyng time (GET) and to evaluate the effect of metoclopramide, a dopamine antagonist that stimulates gastric motility, to gastric emptying. The normal value for biological gastric emptying half time was found to be 63±7 minutes, and the gastric emptying was monoexponential fashion, at least for the first 60 minutes. Among the 20 volunteers, nine were repeated the test after injection of metoclopramide, which has significant1y reduced the value of GET to 31±3 minutes (p〈0.01). GET test using Tc-99m-DTPA is very useful in gastric function evaluation, especially in follow-up check of the functional change