Acid reflux is another term for a condition many people commonly call heartburn. It primarily affects the food pathways, so it can cover a range of conditions that have almost identical characteristics. Each of us uses hydrochloric acid in our gut to breakdown the food we eat and ideally that is where it should stay. The sensation of burning that can be felt in the area of the stomach and heart happens when the digestive fluid tries to travel up the food tract.
Food is normally trapped in the stomach by the lower esophageal valve after it has passed through to stop this problem. The esophageal sphincter should close and trap the acid but when this doesn't happen and the acid escapes back u