The reactive hemophagocytic syndrome may mimic acute hepatitis, as we report here. It should be considered when hepatitis is accompanied by high fever, progressive cytopenias, and weight loss, with or without adenopathy and striking lactate dehydrogenase elevation. Bone marrow, lymph node, or liver biopsy are necessary to confirm the diagnosis. Recognition is important, because the syndrome has multiple potential causes amenable to therapy. Preliminary reports suggest that high-dose corticosteroid therapy is useful in suppressing cytokine-stimulated fever and hemophagocytosis, whatever the underlying cause.