The effect of two-hour infusions of metoclopramide at five different doses on interdigestive intestinal electrical activity was studied in four conscious fasting dogs. Spike activity during the infusions was quantitatively compared with activity during preceding and following periods of saline infusion. The effect of the drug was the enhancement of spike activity during migrating myoelectric complexes (MMC) without disruption of the fasting pattern; the effect was most marked in the proximal small intestine and diminished distally. As in other published studies with metoclopramide, its effects were variable and not dose dependent. The enhancement of the MMC by an exogenous stimulus, not previously reported, provides indirect evidence for cholinergic mediation of cyclical motor activity, and also suggests a rational basis for therapy.