Nephrolithiasis is associated with a variety of abnormalities in urinary 
composition. These abnormal urinary risk factors are due to dietary 
indiscretions, physiological-metabolic disturbances or both. Stone disease is 
morbid and costly, and the recurrence rates may be as high as 30-50% after 5 
years. Efforts to prevent stone formation are, therefore, essential. Dietary 
factors play an important role in kidney stone formation. Tailored dietary 
recommendations based on metabolic evaluation should be offered to patients for 
the prevention of recurrence of stone formation. Dietary intervention and 
subsequent evaluations of therapeutic efficacy should be based on results from 
multiple 24-h urine collections. Urine flow of >1 ml/kg/h almost eliminates the 
risk of supersaturation for calcium oxalate, calcium phosphate and uric acid, 
thus protecting from the formation of corresponding kidney stones. In patients 
with cystenuria, the required urine flow may even be higher and, in cases such 
as primary xanthinuria, high fluid intake is required. Milk intake in these 
patients should be within the RDA of calcium and protein. In children, 
recommendation of a high fluid intake has only limited success. Nevertheless, 
each patient should be advised about adequate fluid intake to increase urine 
volume in accordance with body size. Although children with hypocitraturia may 
benefit from therapeutic agents that raise the urine citrate concentration, all 
children bearing residual fragments should be counseled on adequate fluid intake 
along with potassium citrate treatment to prevent stone regrowth or formation.