Sometimes referred to as GER, heartburn (which is actually just a symptom of reflux) or acid reflux, reflux is the backward flow of stomach contents up the esophagus and sometimes out the mouth. The esophagus is a long tube that carries food and liquids from your mouth to your stomach. At the lower end of the esophagus, a valve called the lower esophageal sphincter, or LES, opens when you swallow to let food and liquids into your stomach, and then closes again to keep stomach contents in their place.

When the LES doesn't function properly it allows stomach contents including hydrochloric acid to back up into the esophagus. This is what causes the pain and damage from reflux. Our stomachs have a protective lining to protect itself from the naturally occurring acid, the esophagus, throat, nasal cavities, lungs and teeth do not. Over time, repeated exposure to these areas by acid can cause increasing damage and cause more serious complications.

It is thought that about one third of the adult population experiences reflux at least once a month and that about 10% of the population experiences reflux weekly or daily. As well, at least 50% of infants are born with some degree of reflux simply from immaturity of the LES. Most of these infants will not have complications and will outgrow it before they are a year old. It is estimated that about 3% will not outgrow it and will experience the more serious complications related to GERD.

When a baby throws up after nearly every feeding and numerous times between feedings, parents may grow concerned and that there is something seriously wrong with their baby and they seek medical advice. Fortunately, most babies will spit up and/or throw up from their reflux and never have any other problems, they will likely outgrow the condition by the time they are one year and will never need medical treatment.

Reviewed By Dave Olson, MD
Fellow, American Academy of Pediatrics
Graduate University of Michigan School of Medicine