Acid reflux occurs when acid backs up from the stomach into the esophagus. This is common but can cause complications or bothersome symptoms, such as heartburn. One reason this happens is that the lower esophageal sphincter (LES ) is weakened or damaged.

Acid reflux occurs when stomach contents move up into the esophagus. It is also known as acid reflux or gastroesophageal reflux (GER). If you experience acid reflux symptoms more than twice a week, you may have a condition called gastroesophageal reflux disease (GERD). If left untreated, it can sometimes lead to serious complications.