Hemophagocytic syndrome in four patients and Literature Review. Hemophagocytic syndromes (HS) represent a severe hyperinflammatory condition with the cardinal symptoms comprises a prolonged fever, cytopenias, hepatosplenomegaly, and the hemophagocytosis by activated, morphologically benign macrophages. The clinical course resembles sepsis, sharing similar physiopathological features. Biochemical markers include elevated ferritin and triglycerides, and low fibrinogen. Whereas in children several inherited immune deficiencies may lead to this syndrome, most adult with HS have no known underlying immune defect. Nevertheless, impaired function of natural killer cells and cytotoxic T-cells is characteristic for both genetic and acquired forms of HS. Frequent triggers are infectious agents, mostly viruses of the herpes group and the malignant lymphomas. A special form of HS in rheumatic diseases is called macrophage-activation syndrome. Patients with HS cannot control the hyperinflammatory response which, if untreated, is fatal in genetic cases and the in a high percentage of acquired cases. Awareness of the clinical symptoms and of the diagnostic criteria of HS is important to start life-saving therapy in time. We present four patients and discuss current therapeutic approaches.