We report a woman presenting with unrelenting odynophagia and chest pain. Computed tomography identified a deep neck infection with acute phlegmonous esophagitis. However, esophageal intramural dissection with mucosal rupture occurred after routine nasogastric-tube insertion, and pus was vomited thereafter. The patient was treated with antibiotics and delayed endoscopic closure of the rupture site and made a full recovery. Although the definite pathogenesis remained unclear, esophageal intramural dissection with mucosal rupture, a possible and rare complication of nasogastric-tube insertion, eventually alleviated the acute phlegmonous esophagitis in our patient.