What condition is described as backflow of gastric contents into the esophagus?

Gastroesophageal reflux disease (GERD) is characterized by the backflow of gastric contents into the esophagus due to a dysfunction of the lower esophageal sphincter. This backflow can lead to symptoms such as heartburn, regurgitation, and discomfort in the chest or throat. In GERD, the acidity of the stomach contents can irritate the lining of the esophagus, resulting in inflammation and, if left untreated, can lead to more serious complications such as esophagitis or Barrett's esophagus.

In contrast, a hiatal hernia involves a portion of the stomach pushing through the diaphragm into the chest cavity, which can contribute to GERD but is not synonymous with the disease itself. Peptic ulcer disease involves the formation of ulcers in the stomach or the upper part of the small intestine, which is a different condition focusing more on gastric mucosal damage rather than reflux of contents. Chronic gastritis refers to the long-term inflammation of the stomach lining, which can cause discomfort but is also not characterized by reflux. Thus, GERD is the correct answer, as it specifically describes the condition of gastric contents backflowing into the esophagus.