Chromoendoscopy using Lugol's iodine solution is widely used to improve the detection of esophageal dysplasia or early squamous carcinoma. Although the solution helps to notice esophageal lesions and to delineate the lesions more clearly, it can cause mucosal irritation leading to retrosternal pain and epigastric discomfort infrequently. We report a case of acute gastric mucosal injury after application of Lugol's solution during chromoendoscopy in a 63-year-old woman. (Korean J Gastrointest Endosc 2010;41:224-227)