Seven patients, who satisfied the criteria laid down by Mason and Barnes (1969) for inclusion under the heading Behçet's disease, were assessed clinically and investigated with particular reference to immune status and blood fibrinolytic activity. In one patient in whom it was possible to obtain an eye for examination, there was evidence, on microscopic examination, of an immune vasculitis as well as clot formation, particularly in the veins. All the patients were treated with fibrinolytic agents and the favourable results obtained with this treatment suggest that it should be considered as the first line of therapy in what is otherwise a very difficult condition to manage.