Infrequent reflux of stomach contents into the esophagus is common in healthy individuals. The lower esophageal sphincter (LES) normally opens to release gas after meals.
Gastroesophageal reflux Disease(GERD) occurs when stomach contents reflux, or back up, into the esophagus for prolong period and thus lead to esophagitis.
GERD is common in healthy infants. More than half of all babies experience reflux in the first 3 months of life, but most stop spitting up between the ages of 12 to 24 months. Only a small number of infants have severe symptoms.