The 2003 Asia-Pacific Conference on Gastroesophageal Reflux Disease (APCCG) defines GERD with mucosal breakdown as a break in the esophageal mucosa of any length due to GERD, and GERD without mucosal breakdown as GERD with typical symptoms, including heartburn and acid reflux, as well as chest pain and extraesophageal GERD without mucosal breakdown is defined as GERD with typical symptoms, including heartburn and acid reflux, as well as chest pain and extraesophageal manifestations (cough, asthma, hoarseness, etc.), but without endoscopic manifestations of esophageal mucosal breakdown. According to the European Genval Working Group, patients with GERD should include those at risk of clinical complications due to GERD and those presenting with reflux-related symptoms with or without significant clinical impairment. The clinical diagnosis of GERD should begin with a proper understanding of the meaning of heartburn and acid reflux, and the APCCG believes that the diagnosis of GERD should be considered first when symptoms of heartburn and/or acid reflux are predominant, unless other diseases are confirmed. However, in Asia, the meaning of heartburn and acid reflux is not well understood by many physicians and patients, and therefore the presence of these symptoms needs to be A lot of detailed description is needed to determine if these symptoms are present. The diagnosis of GERD is supported by the fact that patients with heartburn who are treated with a proton pump inhibitor (PPI) have a significant effect. In Asia, heartburn can also be a symptom of peptic ulcer patients. In addition, patients with GERD may also present with dyspepsia. Endoscopy is the “gold standard” for the diagnosis of GERD with mucosal breakdown, and it plays an important role in the diagnosis of GERD. The presence of esophageal erosions, ulcers, strictures, Barrett’s epithelium and esophageal cancer can be determined by microscopy, and other upper gastrointestinal diseases can be excluded. Endoscopy can also provide microscopic diagnosis and treatment for patients with GERD with complications. Currently, there is no “gold standard” for the diagnosis of GERD without mucosal breakdown. The role of high-definition magnification endoscopy in the diagnosis of GERD without mucosal rupture needs to be further investigated. The commonly used endoscopic criteria for the diagnosis of GERD with mucosal breakdown are the Los Angeles Classification (1994), which has become a universal clinical classification because of its reproducibility. Tokyo classification (1996) and our Yantai classification (1999). Histopathological examination: To determine the presence of Barrett’s epithelium and esophageal cancer, the histological abnormalities of GERD include a series of features suggestive of epithelial damage and repair. These changes, although not specific, are sufficient to demonstrate the characteristics of GERD. Epithelial hyperplasia is manifested by thickening of the basal layer by more than 15% of the entire epithelial thickness (hyperplasia of more than 3 layers) and extension of the papillary bulge of the lamina propria by more than 2/3 of the epithelial thickness. these changes suggest accelerated epithelial proliferation and renewal. These changes can be seen in the distal esophagus (2-3) cm in normal individuals and can be a manifestation of transient reflux in healthy individuals. Another indication of epithelial damage is ballooning, i.e., swollen round squamous cells with lightly stained cytoplasm. The lamina propria of the mucosa in GERD is reflected by marked capillary dilation and congestion, with vascular lakes or hemorrhage at superficial papillae. Intraepithelial eosinophils are another indication of GERD, but are only seen in 30% to 50% of GERD patients. Intraepithelial lymphocytes are a normal indication of esophageal mucosa, but as a part of the inflammatory response to GERD, the number of lymphocytes may increase, sometimes significantly. Typically, normal specimens have fewer than 10 lymphocytes per high-powered view, whereas GERD can have more than 20. Neutrophil infiltration is an insensitive diagnostic indicator and is seen in only 15-30% of cases. Mucosal erosions and ulcers are signs of a broken esophageal mucosa, and pathologic histology can determine the presence of Barrett’s epithelium, abnormal esophageal development, and esophageal cancer. Currently, there are no pathological criteria for the diagnosis of GERD without mucosal breakdown.