Gastroesophageal reflux disease (GERD) happens when acidic stomach contents flow back up into the esophagus. This is known as acid reflux. It’s possible to have GERD without esophagitis, or inflammation of the esophagus. This is often related to PPI therapy, which lowers the acidity of reflux. However, because PPIs don’t control the reflux itself, symptoms such as regurgitation may persist.