The dentate line of the esophagus is located in the lower part of the esophagus, at the junction of the esophagus and the stomach. Generally, the esophageal mucosa is light red and the gastric mucosa is orange. At the demarcation point of the dentate line, it is obvious that the esophageal mucosa turns into the gastric mucosa, so this place is the demarcation line between the esophagus and the stomach. When doing gastroscopy, it is possible to clearly delineate the junction point between esophageal mucosa and gastric mucosa through the demarcation line, and it is also possible to see whether there is reflux esophagitis, or esophageal hiatal hernia, etc. through this location. Therefore, the dentate line is an anatomical demarcation point that can clearly observe the junction of the esophagus and the stomach.