Gastroesophageal reflux disease (GERD) is the reflux of gastroduodenal contents into the esophagus, causing symptoms such as acid reflux, heartburn, regurgitation and belching, and can lead to esophagitis, damage to extraesophageal tissues such as the pharynx, larynx and airway. Esophageal lesions can be complicated by esophageal erosion, ulcers, and esophageal cancer. Extra-esophageal manifestations can be seen in chronic pharyngitis, chronic rhinitis, chronic laryngitis, chronic bronchitis, bronchial asthma, bronchiectasis, interstitial fibrosis, and other manifestations such as non-cardiogenic chest and back pain and sudden deafness. In Western countries, 7%-15% of the population has GERD symptoms, and in China, according to the survey statistics in Beijing and Shanghai, nearly 10% of people suffer from GERD.