A stricture is a narrowing in a tube. It is like a dam across a stream which obstructs the flow. Strictures most often are benign and caused by acid refluxing into the lower esophagus. As this inflamed tissue breaks, scar formation occurs and causes contraction, much as a burn injury does to the skin. In time, the narrowing can become quite severe and obstruct the flow of food into the stomach. Image 1 shows a very tight, fixed stricture measuring only about 1/4 inch across. In Image 2, the stricture is not as tight, and measures perhaps 1/2 inch. This picture illustrates the inflammation and ulceration of the esophagus which leads to the stricture. Fortunately, most strictures can be effectively relieved.