“A muscle that controls the passage of foods and fluids we eat is between the esophagus and stomach, and when it doesn’t close completely, stomach acid and food flow back into the esophagus. The medical term for this process is gastroesophageal reflux (GERD); the backward flow of acid is called acid reflux=digestive acids coming back during digestion, the acids should normally stay in the stomach.”.

Harvard Health Publishing