Gastroesophageal reflux (GER) occurs when there is an involuntary retrograde passage of gastric contents into the esophagus with or without regurgitation or vomiting. GER disease (GERD) occurs when reflux of the gastric contents causes symptoms that affect the quality of life for an infant. The predominant cause of GERD is transient lower esophageal sphincter (LES) relaxation. Regurgitation and vomiting are the most common symptoms of infant reflux. In GERD, the reflux contains stomach acid which damages the lining of the esophagus. Feeding changes may be necessary. Medication and surgery may be necessary dependent on severity. Learn more at NIH.