Causes

GERD is caused by frequent acid reflux.

When you swallow, a circular band of muscle around the bottom of your esophagus (lower esophageal sphincter) relaxes to allow food and liquid to flow into your stomach. Then the sphincter closes again.

If the sphincter relaxes abnormally or weakens, stomach acid can flow back up into your esophagus. This constant backwash of acid irritates the lining of your esophagus, often causing it to become inflamed.