A 58-year-old woman with lung cancer complaint odynophagia by sour food. Endoscopic examination revealed severe erosion strictly limited to the esophagus. Drug-induced esophagitis was suspected. She was taking afatinib, loxoprofen, pregabalin, lorazepam, a formulation of butyric acid bacteria, and amino acid supplements for more than 1 month at the time of developing esophagitis. Her appetite was very poor for several days before developing the esophagitis. Although not definitive, the most probable cause of her esophagitis is an increased blood concentration of afatinib due to prolonged starved condition.