Gastroenterology Consultants,SC: Diseases of the GI tract [<<back | list all>>] ESOPHAGITIS AND STRICTURE A specialized muscle, known as the lower esophageal sphincter (LES), is located at the end of the esophagus. This muscle normally contracts firmly, relaxing only to allow food and liquid to pass from the esophagus into the stomach. This muscle maintains a certain pressure to keep the end of the esophagus closed, preventing stomach acid and digested food from moving back into the esophagus. The LES muscle does not always work perfectly. It can easily be overcome by a number of factors, the most common being eating a large meal. When stomach acid and digestive enzymes repeatedly reflux into the esophagus, the tissues become inflamed and ulcerated. This inflammation is known as esophagitis. When the inflammation is severe, esophageal ulcers develop and may develop into cancer over a period of time.