The backflow of stomach acid and mucus secretions into the esophagus can lead to reflux symptoms. These symptoms may include a burning sensation in the esophagus and chest, difficulty swallowing, a burning sensation when swallowing, and the taste of bitter fluid in the mouth. Since stomach acids are not visible to the naked eye, a definitive diagnosis of reflux cannot be made without measuring the acid levels in the stomach and esophagus. At this critical juncture, the pH meter device, an endoscopic method, is effectively used in the accurate diagnosis of reflux disease.