Gastroesophageal reflux disease (GERD)

When we eat, food is carried from the mouth through the esophagus, a tube-like structure that is approximately 10 inches long and 1 inch wide in adults. At the lower end of the esophagus, where it joins the stomach, there is a circular ring of muscle that relaxes and opens when food reaches that point, called the lower esophageal sphincter (LES). This allows food to enter the stomach and then closes to prevent the back-up of food and acid into the esophagus. Reflux can occur if the LES is weak or stays relaxed too long.