Gastroesophageal reflux disease, or GERD, is a chronic digestive disease. It occurs when stomach acid or, occasionally, bile flows back into the esophagus.

If you have ever experienced heartburn that travels up your throat and into your mouth, leaving a sour taste behind, it may be due to bile acid in your stomach. When this fluid fills your stomach, its cause is bile reflux, a condition often related to acid reflux.

The average person may not experience heartburn as often as pregnant women and older adults, but it’s still one of the most common digestive complaints. A random bout of heartburn can usually be linked to something specific, such as a large meal, a spicy dish or too much caffeine.

Gastroesophageal reflux disease or GERD occurs when stomach acid and/or bile flows back into your esophagus, the pipe that allows food to travel from the mouth to the stomach. This process of acid backflow is called reflux. The acid can irritate the lining of your esophagus and cause heartburn, the chief GERD symptom.

Nexium and Prilosec are drugs that belong to a class of medications known as proton pump inhibitors. Proton pump inhibitors are drugs that decrease production of acid in the stomach in order to allow sores in the lining of the stomach and esophagus to heal.

Histamine is a substance released by the body's immune system from cells called mast cells. This occurs in response to injury or allergies. Histamine receptors are the proteins on cells found in the brain, blood vessels, lungs, skin and stomach that bind to histamine in order to produce an inflammatory response.

Barrett's esophagus occurs when changes develop in the tissue that lines the lower part of the esophagus, where the stomach and esophagus meet. The condition usually develops as a result of repeated damage from longstanding gastroesophageal reflux disease, or GERD.

Proton pump inhibitors, or PPIs, are medicines that help reduce the acid production in the stomach. PPIs work by interfering with the mechanism that pumps acid into the stomach, states the National Digestive Diseases Information Clearinghouse.

It can be very uncomfortable when your throat feels tight. If you do not know why your throat feels tight, this may even make you feel alarmed. Depending on the cause, the problem may be constant or intermittent.

The symptoms of gastroesophageal reflux disease, known as GERD, are provoked by leaking of stomach contents into the esophagus, according to the American Gastroenterological Association. GERD is diagnosed when symptoms are suffered more than twice weekly.

When you have heartburn -- a painful, burning sensation behind or below the breastbone -- you might be quick to blame it on something you ate. But persistent or frequent heartburn that disrupts your well-being or daily life might be more than a matter of your diet.

Toddlers are prone to stomach upset, due in part to the immaturity of their digestive system. Acid reflux -- the backward flow of stomach contents into the food pipe, or esophagus -- is very common and usually harmless in infants.