Phlegmonous gastritis is an uncommon acute bacterial infection of the stomach that carries a fatal prognosis in spite of the advent of antibiotics. A high index of suspicion is required in patients with risk factors. An immunocompromised state is identified as one of the most important risk factors. We hereby report a case of successful antimicrobial treatment of phlegmonous gastritis in a patient who was receiving intensive chemotherapy for acute myelogenous leukemia. We have also carried out a review of literature over the past ten years. Streptococcus pyogenes is identified as the most common causative organism, and patient presentation is usually nonspecific. Conservative treatment with prompt institution of antibiotics can lead to rapid resolution in the majority of patients.