Nifedipine, a calcium channel blocker, inhibits lower esophageal sphincter pressure but has only minimal effect on esophageal contractions. We investigated the effects of nifedipine on esophageal contractions in 5 healthy volunteers and 10 patients with the nutcracker esophagus. Nifedipine (10, 20, 30 mg) or placebo was ingested as capsules in a double-blind design on 4 separate days. In volunteers, mean distal amplitude decreased 16.6%, 38.4%, and 49.0% as the nifedipine dose was increased. These changes were significantly (p less than 0.05) different from the placebo response and were sustained with higher doses. Patients with the nutcracker esophagus had a similar response, decreasing mean distal amplitude significantly (p less than 0.05) by 16.3%, 36.2%, and 54.2%. In both groups, nifedipine also had a significant (p less than 0.05) dose-dependent depressant effect on distal duration, although to a lesser degree than on amplitude. The percent decrease in distal amplitude showed good correlation (p less than 0.01) with plasma nifedipine concentrations at 60 min. These studies suggest nifedipine may be useful in the treatment of motility disorders of the esophageal body.