The evaluation of suspected esophageal chest pain is frustrating because of difficulty in clearly implicating the esophagus. Balloon distention was considered as a new provocative test in the esophagus because it has been shown to safely produce pain in other hollow gastrointestinal organs. Studies were performed in 50 chest pain patients ( [`(X)]\bar X age 50 years) with negative coronary arteriograms and 30 healthy volunteers ( [`(X)]\bar X age 41 years). A polyvinyl balloon (length 30 mm; maximum diameter after 10 cc distention 25 mm) was positioned 10 cm above the lower esophageal sphincter and inflated with 1-cc increments of air to a total volume of 10 cc. Using a placebo-controlled design, pain response was recorded along with associated balloon volumes. Pain occurred in 28/50 (56%) patients and 6/30 (20%) volunteers (P<0.005). Symptoms were unassociated with ECG changes, and resolved immediately with decompression of the balloon. Most patients (24/28) experienced their typical chest pain at 8 cc distention, while all volunteers with pain noted it at 9 cc distention. For this reason, 8 cc was considered a diagnostic cutoff. Chest pain patients were also studied with two other commonly used provocative tests: intraesophageal acid perfusion and intravenous edrophonium (80 g/kg). These tests reporduced pain in only 12 (24%) patients. Positive balloon studies occurred in 11 of these patients and identified an additional 13 patients, thus increasing the diagnostic yield from 24% to 48%. Only one of 22 (4%) balloon-negative patients had a positive acid-perfusion or edrophonium test.