To make an accurate diagnosis of esophageal rupture during balloon dilatation without the help of esophagograph, an infusion pump, a pressure transducer and a radiopaque esophageal balloon were connected through a three-way connector. The pressure transducer was connected consecutively to an amplifier, a differentiator and a speaker to detect a pressure drop in the esophageal balloon. Under fluoroscopic monitoring, a radiopaque balloon catheter was inserted in the mid-thoracic esophagus of 30 rabbits and inflated with air until the esophagus was ruptured. A pressure drop in the balloon at the time of esophageal rupture was not only recorded graphically, but also was identified through a speaker. To examine esophageal rupture grossly, the rabbits were sacrificed after esophagography. We could detect the time of esophageal rupture during balloon dilatation in all rabbits accurately by observing the pressure drop on the pressure recorder and by hearing the sound made on a speaker. In 8 patients with esophageal stricture, a deflated radiopaque balloon catheter was inserted to the position inside the narrowing point and inflated by injecting air until the 'hourglass' deformity created by the stricture disappeared from the balloon contour which the pressure change in the balloon was monitored with a pressure recorder. The balloon pressures at the time of disappearance of the "hourglass" deformity from the balloon contour ranged from 200 mmHg to 2000 mmHg in 8 patients with esophageal strictures. Esophageal ruptured did not occur in these patients. In conclusion, our results indicate that this new method is not only safe but promising for patients in the future with esophageal strictures. First, it would reduce the chance of mediastinitis in patients of esophageal rupture. Second, esophageal balloon dilatation can be performed more effectively and safely. Third, it is cost-effective. Forth, radiation esposure to the patient can be reduced.