Abstract We studied effects of i.v. atilmotin (BAX-ACC-1638, a novel motilin agonist, circulating t1/2 <10 min) on gastrointestinal transit in humans using a randomized, parallel-group, dose-response double-blind study of i.v. atilmotin, 6, 30, 60 μg or vehicle (placebo) given 2 min after standardized breakfast, lunch and dinner. The breakfast meal contained 99mTc-eggs and 111In-milk. Full gastrointestinal transit was measured by scintigraphy. Primary endpoints were % gastric emptying (GE) at 30 min, GE t1/2, colonic filling (CF) at 6 h, and geometric centre of colonic transit at 24 h. Analysis included adjustment for age, gender and body mass index, with Bonferroni correction applied for multiple comparisons. A significant treatment effect of atilmotin was detected for GE (%) at 30 min for solids and liquids (P < 0.01 for both). There were no significant effects on CF or CT and no significant adverse clinical events. Thus, atilmotin accelerates GE of solids and liquids in healthy humans. These data suggest that, at the doses tested, atilmotin should be considered for treatment of stomach motility disorders.