Behçet's syndrome is a systemic vasculitis with an unknown etiology affecting the small and large vessels of the venous and arterial systems. At least two clusters of disease expression have been described. The first includes superficial vein thrombosis, deep vein thrombosis, and dural sinus thrombi. The second includes acne, arthritis, and enthesitis. The presence of these clusters suggests there may be more than one disease mechanism operative in this complex disorder. Recent European League Against Rheumatism guidelines are useful for the management of the disease in organ systems distinct from the vascular, neurological, and gastrointestinal systems. This is because of a lack of controlled studies evaluating such vascular, neurological, and gastrointestinal complications.