Behçet disease is an idiopathic, multisystem, chronic, and recurrent disease characterized by exacerbations alternating with phases of quiescence, episodic panuveitis, and aggressive non-granulomatous occlusive vasculitis of the arteries and veins of any size with explosive ocular inflammatory attacks that primarily affect the retinal and anterior segment vasculature of the eye. The disease is characterized by endothelial dysfunction and may produce a wide variety of symptoms. In mild cases, orogenital ulcers and skin lesions are the only findings during the entire clinical course, whereas ocular lesions that occur in more than half of the cases, frequently bilateral, can eventually lead to blindness. Pulmonary, gastrointestinal, and central nervous system involvements may sometimes be life-threatening. This review examines the epidemiology, frequency, immunology, and immunohistopathology of Behçet disease with recent theories of several agents, including phosphoantigens, superantigens, heat-shock proteins, and adenosine deaminase. Perspectives on the possible roles of new etiopathological molecules, such as nitric oxide, endothelin, and homocysteine, are presented. Ocular and systemic clinical features, diagnostic criteria, classifications, laboratory, fundus fluorescein angiography, and radiologic imaging are discussed. Differential diagnosis, disease in pregnancy and childhood, and prognosis with regard to Behçet-induced systemic and ocular complications are also evaluated. Traditional and current treatments with topical, paraocular and systemic corticosteroids, colchicine, dapsone, cyclosporine, azathioprine, methotrexate, cyclophosphamide and chlorambucil are summarized and recent insights into the pharmacology and effects of thalidomide, tacrolimus (FK-506), interferon-alpha, anti-TNF-alpha blocking monoclonal autoantibody (infliximab) and soluble TNF receptor (etanercept) are reviewed. Key clinical investigations with the status of ongoing clinical trials aimed at addressing the drug's efficacy, surgical care, and studies that have raised the possibility of new therapeutic uses are also presented. The challenges posed by the drug's teratogenicity and adverse effects are also considered, if present.