Gastroesophageal reflux disease, also know as GERD, occurs when the lower esophageal sphincter (LES), a muscle at the end of the esophagus doesn’t close properly. This causes stomach acid used for digestion to back up, or reflux into the lower esophagus. When stomach acid comes in contact with the lining of the esophagus, it can cause heartburn, among other symptoms. More than 60 million Americans experience heartburn or GERD symptoms at least once a month. To help treat and prevent GERD, take action by following these simple steps.