Chronic urinary tract infections by urease-producing bacteria may increase urine pH and promote thereby the formation of recurrent kidney stones made of highly carbonated calcium phosphate apatite and struvite, a magnesium ammonium phosphate. To date, there is no safe and effective treatment decreasing urine pH on a long term. We hypothesized that fludrocortisone, a mineralocorticoid, would decrease urine pH by increasing proton secretion in the kidney collecting tubule. We report three cases of patients with kidney stone suffering from chronic urinary infection by urease-producing germs, treated by fludrocortisone on a long term. Urine pH decreased sustainably over several months and tolerance was good
