What causes acid reflux?

Why acid reflux occurs

Stomach acid, which we need to digest our food, is not a problem when it stays where it belongs—in your stomach.

Acid reflux is a physical condition where the contents of the stomach—including acid—back up (or reflux) into the esophagus (the tube that carries food from your mouth to your stomach). If this condition happens too frequently, it could cause acid reflux disease.

The role of the LES

Between your esophagus and your stomach there is a natural barrier, or valve, called the lower esophageal sphincter (LES). For most people, the LES works just fine. But for some people with acid reflux disease, this valve does not always work the way it should for 2 reasons:

It relaxes too frequently

It's too weak

Damage to the esophagus

The lining of your stomach is built to handle stomach acid. But the lining of your esophagus is not. It can protect itself for a while, but when acid comes in contact with this lining for an extended period of time, it can lead to serious damage. And as a result, you may experience heartburn and other painful or uncomfortable symptoms.

If left untreated, acid reflux disease may even cause damage (erosions) to the lining of the esophagus, a condition known as erosive esophagitis. If you have any concerns about your symptoms, please be sure to talk to your doctor.

Next: What happens?