The present study investigated how reflux-induced esophagitis affects the smooth muscle reactivity of the esophageal body. Two different esophagitis models were used: acid gastric and mixed duodenogastric reflux. All test animals apart from the controls developed gross and histologic evidence of esophagitis. Contractile (carbachol and KCI) and relaxant (isoproterenol) esophageal smooth muscle responses were significantly decreased in the presence of acid- and mixed reflux-induced esophagitis. Similar relaxant responses to serotonin and papaverine were found in the three groups. Our study demonstrated impaired esophageal smooth muscle reactivity when esophagitis was induced by acid or mixed reflux. These changes may correspond to the functional motor abnormalities of the esophagus seen in patients with reflux esophagitis.