Gastroesophageal reflux disease, or GERD, is a condition in which stomach contents splash up into the esophagus. The esophagus is a narrow, muscular tube that carries food from the mouth to the stomach.

What is going on in the body?

The esophagus is connected to the stomach by the esophageal sphincter. This is a muscular ring. Normally, this muscle performs two major functions. It opens to allow food to pass into the stomach. It also closes to keep the stomach contents out of the esophagus.

If this sphincter weakens or relaxes, the contents of the stomach splash back up into the esophagus. This splashing is known as gastroesophageal reflux.

What are the causes and risks of the disease?

GERD can be caused by a weak esophageal sphincter that is present at birth or that develops later in life. A hiatal hernia can also cause GERD. Hiatal hernia is a condition in which the stomach pushes up into the diaphragm muscle. When this happens, the esophageal sphincter does not work properly. As a result, the fluid can easily leak back into the esophagus.

Factors that make GERD worse include the following: