Effects of trimebutine maleate (TM-906) on gastrointestinal motor activity of interdigestive state were studied in seven unanaesthetized dogs by means of chronically implanted force transducers. In animals which showed typical interdigestive motor pattern consisted of long lasting motor quiescence and recurring high-amplitude contractions (interdigestive contractions), intravenous infusion of TM-906 (0.6-6.0 mg/kg-hr) shortened the quiescent period. During TM-906 infusion, the number and the duration of the interdigestive contractions decreased in the gastric antrum. These effects were in a dose dependent manner. Infusion of TM-906 of 6.0 mg/kg-hr over 60 min introduced additional responses: persistent contractions different from the usual interdigestive contractions and delayed onset of the interdigestive contractions. Metoclopramide (1.8-6.0 mg/kg-hr) developed high-frequency contractions with gradually increasing amplitude and caused enhancement of the interdigestive contractions. In three animals which showed anomalous fasted motor pattern consisted of continuous low-amplitude contractions, bolus i.v. injection of TM-906 (2.0-2.5 mg/kg) introduced a transient suppression of the contractions in the antrum. Metoclopramide (1.0 mg/kg i.v.) potentiated and hyoscine-N-butylbromide (0.1 mg/kg i.v.) inhibited the contractions in all the regions.