This article discusses the therapy of diabetes mellitus. Apparently long forgotten by modern biomedical science, these findings have taken on new meaning with several recent discoveries. The pathogenesis of diabetes mellitus was poorly understood in the nineteenth century and is only partially understood today. Insulin insufficiency is relative in type 2 diabetes, as significant levels of insulin are generally found in the circulation. High-dose salicylate, used throughout the twentieth century to treat acute rheumatism and rheumatoid arthritis, remains a common treatment today at 3 g/day.