Thirty-four consecutive patients referred to a gastroenterology clinic with suspected esophageal motility abnormality as a cause of their chest pain or dysphagia, or both, were prospectively studied in an 18-mo period. Peristaltic response to 10 wet (5 ml H2O) swallows was recorded in all studies with a low-compliance infusion system. To provoke symptoms and motility abnormalities after baseline evaluation, all patients had acid infusions (0.1 N HCl) and administration of edrophonium (80 micrograms/kg i.v.), pentagastrin (6 micrograms/kg s.c.), and bethanechol (40 micrograms/kg s.c.). Tracings were coded, read, and interpreted blindly. Baseline tracings were abnormal in 23 of 34 patients (68%), including increased amplitude peristaltic contractions ("nutcracker esophagus") in 10 and nonspecific esophageal motor disorders in 13. Acid infusion produced substernal burning in 3 of 33 patients, in motility change in 1 patient. Edrophonium produced chest pain with manometric changes in 6 of 34 (18%) patients. Pentagastrin produced chest pain with manometric change in 1 patient. Bethanechol produced chest pain with manometric change in 2 patients. One patient with low amplitude had elevation of esophageal baseline and multiple simultaneous contractions but no chest pain (subsequently developed achalasia). It was concluded that (a) abnormal motility is a common finding in a symptomatic group of patients with presumed esophageal motility disorder, (b) the "nutcracker" esophagus is the most frequent defect, and (c) attempted provocation of symptoms with acid or drugs is not generally effective; however, edrophonium is the best tolerated and most effective of currently available drugs.