The effect of AS-4370 given in single doses of 2.5, 5 and 10 mg on gastric emptying was investigated using 99mTc-DTPA in healthy volunteers in the placebocontrolled double-blind crossover design. There was no difference in percent activity throughout the period of measurement between AS-4370 2.5 mg and placebo. The percent activity decreased after administration of 5 and 10 mg of AS-4370 in comparison with placebo: the decrease was found during the period from 10 to 18 minutes after start of recording at 5 mg and from 8 to 18 minutes after start of recording at 10 mg. These results demonstrated that AS-4370 at these dose levels apparently accelerated gastric emptying. The analysis of the half emptying time by the crossover method showed that only the time effect was found at 2.5 mg, whereas the half emptying time was obviously shortened at 5 and 10 mg. There was no difference between 5 mg and 10 mg. There was no finding that might warrant a caution in terms of safety. In conclusion, AS-4370 did not affect gastric emptying at 2.5 mg but apparently accelerated gastric emptying at 5 and 10 mg in healthy volunteers.