Control of Paget's disease of bone has been possible through treatment with agents that decrease bone resorption; calcitonins, diphosphonates, and mithramycin. The pagetic lesion is not, however, cured. Etidronate disodium is one of the diphosphonates. The clinical improvement attained with this drug has to be set against adverse effects, of which pain is probably the most bothersome in practice. Clinical remission can last as long as 2 years after treatment is stopped.