In both Still disease and Wissler-Fanconi syndrome, onset may occur in adulthood and the clinical picture includes acute, often migratory, polyarthritis, polymorphic exanthema and a major inflammatory syndrome with fever (often intermittent) and high polymorphonuclear leukocyte counts. The grounds for this double designation are not clearly stated in the medical literature: does it refer to two separate entities or not? Some authors plainly stand for a unitary opinion. We report on seven cases in adults, five of which recovered without sequellae, while two developed respectively into rheumatoid arthritis and seronegative polyarthritis. We therefore propound a dualistic concept although, in the present state of our knowledge, there is no means of predicting at onset whether the disease will resolve or progress towards polyarthritis. We suggest that the term Still disease be used only when chronic and/or destructive arthritis develops. Among the forms which are neither chronic nor destructive, there seems to be a number of cases in allergic patients with poor tolerance of chrysotherapy. Some of these patients could recover after the cure of an often latent focal infection, usually of the upper respiratory tract, ear or oral cavity, resistant to antibiotics. In the other cases, corticosteroid therapy is usually very effective in arresting an exacerbation of the disease.