The hypertensive peristaltic (nutcracker) esophagus represents a motility disorder characterized clinically by squeezing restrosternal chest pain and manometrically by high amplitude esophageal peristaltic contractions. This study was designed to examine whether the nutcracker esophagus is: (a) a distinct entity, (b) a member of the spectrum of primary esophageal dysmotilities (e.g., diffuse esophageal spasm and achalasia), or (c) is secondary to reflux-induced acid sensitivity. Thirteen patients with a nutcracker esophagus by baseline manometry were subsequently studied after acid perfusion and bethanechol stimulation (0.08 mg/kg). Records were analyzed for symptomatic response and motility changes. Eight of 13 (62%) experienced chest pain during acid perfusion, but none had significant motility changes documented during this period. After bethanechol injection, chest pain occurred in six of 12 (50%) patients; two had burning pain and in the other four (33%) their squeezing chest pain was reproduced. Changes in the motility tracing with evidence of disordered motility suggestive of diffuse esophageal spasm were seen after bethanechol in seven of the 12 tracings analyzed (58%), including all six patients who developed chest pain. We conclude that patients with nutcracker esophagus on baseline manometry may develop motility patterns consistent with diffuse esophageal spasm after provocation with bethanechol. We take this to suggest that the nutcracker esophagus is part of the continuum of primary motility disorders and may actually be a precursor of diffuse esophageal spasm.