Esophageal dilation is a procedure that allows your doctor to dilate, or stretch, a narrowed area of your esophagus [swallowing tube]. Doctors can use various techniques for this procedure. Your doctor might perform the procedure as part of a sedated endoscopy. Alternatively, your doctor might apply a local anesthetic spray to the back of your throat and then pass a weighted dilator through your mouth and into your esophagus. The most common cause of narrowing of the esophagus, or stricture, is scarring of the esophagus from reflux of stomach acid occurring in patients with heartburn.