The esophagus is the tube that carries food, liquids and saliva from your mouth to the stomach. You may not be aware of your esophagus until you swallow something too large, too hot or too cold. You may also become aware of it when something is wrong. The most common problem with the esophagus is gastroesophageal reflux disease (GERD). It happens when a band of muscle at the end of your esophagus does not close properly. This allows stomach contents to leak back, or reflux into, into the esophagus and irritate it. Over time, GERD can cause damage to the esophagus. Other problems include heartburn and cancer . Treatment depends on the problem. Some get better with over-the-counter medicines or changes in diet. Others may need prescription medicines or surgery.