A 17-YEAR-OLD African American girl was seen for severe anemia. She had mild anemia 1 year previously and increased fatigue and shortness of breath for 3 months prior to evaluation. Her history was notable for insulin-dependent diabetes mellitus (IDDM) since age 6 years, Graves disease with hyperthyroidism since age 13 years, and paranoid schizophrenia since age 14 years. Her maternal grandmother and a maternal aunt had vitamin B12 deficiency, and a brother and maternal aunt had IDDM. Two weeks prior to presentation, our patient developed peripheral edema and cold extremities, consistent with florid congestive heart failure; on examination she had pallor, peripheral edema, and a cardiac gallop with evidence of moderate pulmonary edema. She was paranoid and delusional and had received chlorpromazine hydrochloride, insulin, and sertraline hydrochloride on a regular basis. Peripheral blood (Figure 1) showed profound anisocytosis with macro-ovalocytes, numerous microcytes, polychromatophilic cells, basophilic stippling, and nucleated red blood cells. There were scattered hypersegmented neutrophils. Bone marrow aspiration biopsy (Figure 2) revealed hypercellular marrow with profound erythroid hyperplasia, left shift of the myeloid precursors, and marked megaloblastic changes. Her vitamin B12 level was low, and lactic dehydrogenase levels were elevated. Hemoglobin electrophoresis was consistent with β-thalassemia trait. A chest radiograph showed mild cardiomegaly and pulmonary edema. The endoscopic appearance of the gastric mucosa (Figure 3) revealed marked atrophy with absent rugal folds and a diffuse reticular pattern of the mucosa. Gastric biopsy specimens (Figure 4) revealed chronic atrophic gastritis with intestinal metaplasia.