What condition is characterized by the regurgitation of stomach contents into the esophagus?

Gastroesophageal reflux disease (GERD) is characterized by the regurgitation of stomach contents, including acid, into the esophagus. This results from a dysfunction of the lower esophageal sphincter, which is supposed to act as a barrier between the stomach and the esophagus. When this sphincter is weakened or relaxes inappropriately, it allows stomach contents to flow back up, leading to symptoms such as heartburn, chest pain, and regurgitation.

GERD is a common condition and can lead to further complications if untreated, such as esophagitis, where the esophagus becomes inflamed due to the acidity of the stomach contents. While esophagitis can be a result of GERD, it is not the condition that directly describes the regurgitation itself, making GERD the most accurate answer. Other options, such as esophageal varices and oral cancer, do not pertain to the regurgitation of stomach contents and involve different pathological processes.