Modern manometric and scintigraphic techniques were employed in an effort to determine the relationships between esophageal contractions and esophageal transit and clearance. The effects of direct cholinergic stimulation with bethanechol and blockade with atropine were evaluated in a total of 20 normal subjects and 13 patients with symptomatic gastroesophageal reflux. Bethanechol increased the amplitudes of deglutition-induced and distention-induced esophageal contractions, but diminished their propagation velocities. Both esophageal transit and clearance were decreased in patients with reflux, but both were improved after bethanechol. Atropine sulfate decreased the amplitudes of contractions, accelerated their propagation velocities, and delayed esophageal transit and clearance. Both transit and clearance were diminished significantly when reflux patients were compared with normal subjects. The amplitudes of esophageal contraction were significantly lower in patients with reflux than in normal subjects. Neither bethanechol nor atropine affected the incidence of deglutition-induced esophageal contractions. These studies suggest that the efficiency of esophageal emptying may be determined by the amplitudes of esophageal contractions.