Effect of T-1815, a new colonic prokinetic compound, on gastrointestinal motility was studied in anesthetized and conscious dogs fasted for 24 hr before experiment.In anesthetized dogs, intravenous injection of T-1815 in doses of 0.3-3.0 mg/kg caused a biphasic effect on the gastric motility, a slight decrease followed by a slight increase. While the compound elicited only an increase in motility of the duodenum, jejunum and colon. In the colon, high- From the above results, it is concluded that the pharmacological effect of T-1815 on gastrointestinal motility is different from that of the cholinergic agonist. In addition, T-1815 seems to have a characteristic to induce high-amplitude contractions which are known to be closely related to defecation.