Chromoendoscopy using Lugol's solution is effective for the detection of early esophageal squamous neoplasia. However, there is no study to investigate the sequence of Lugol's staining during endoscopic procedure.~The aim of this study is to compare the effectiveness and safety of spraying Lugol's solution from cervical esophagus to esophagogastric junction (downward) and from esophagogastric junction to cervical esophagus （upward）during chromoendoscopy.
The aim of this study is to compare the effectiveness and safety of spraying Lugol's solution from cervical esophagus to esophagogastric junction (downward) and from esophagogastric junction to cervical esophagus （upward）during chromoendoscopy.