Behcet's disease is a recurrent multisystem vasculitis that can affect any organ or system, but was originally described as orogenital ulcerations and uveitis. Specific criteria have been proposed for diagnosis and identification of affected organs by different national authorities. Behcet's disease is proposed to be due to an antigen/antibody reaction. The antigen can be external (microbial or other) or self-antigen. Self-antigens include HLA-B, S and interphotoreceptor retinoid binding protein, the oral mucosal antigens, and alphatropomycin. The antibody reaction manifests as changes common to any inflammatory process. Circulating immune complexes and neutrophil hyperactivity are present with the expression of adhesion molecules related to disease activity associated with phenotypic and functional aberrations affecting both Th1 and Th2 activity. The results in an increase of interleukin-4, -10, and -1B and interleukin-2 receptors with deficient interleukin-12, interferon-gamma, and expression of cell adhesion CDII/CD18, accompanied by increased B cells secreting IgG. The clinical picture varies according to the organ affected; emphasis is placed on those of diagnostic importance and those affecting morbidity and mortality. The histopathology demonstrates vasculitis with inflammatory cell infiltration, the endothelium expressing ICAM-1 and E-selectin, vascular occlusion with sequences. Treatment includes corticosteroids. Other immunosuppressant and biological agents include anti-tumor necrosis factor, interferon-alpha, Campath-1, and the S antigen. Colchicine and other miscellaneous therapies are included.