Acute phlegmonous gastritis, a suppurative infection of the gastric wall, has a high mortality rate. This disease remains a mystery to most clinicians. The rarity of this disease and its nonspecific presentation make early diagnosis difficult, especially in the emergency department. We describe a case of acute phlegmonous gastritis presenting as gastric wall abscess in a 55-year-old woman who visited the emergency department, illustrating the severity of this disease, the difficulty in its diagnosis and its unusual presentation.