Abstract
Certain patients with recurrent calcium oxalate calculi show a mild uricacidemia and/or uricosuria. A prospective blind study was begun in 1970, comparing placebo to allopurinol in the management of these patients. The 92 patients were followed for a minimum of 6 mo.-5 yr before the code was broken. There was a placebo effect in the management of renal calculous disease. It was shown that the only event that clearly separated the 2 groups was complete cessation of calculous formation. Allopurinol was effective in 61% of the patients and these successes were usually identified after 1 yr of treatment.