Nephrolithiasis, or kidney stone disease, is the second most frequent kidney disease after hypertension, affecting up to approximately 20% of men and approximately 10% of women in industrialized countries. The prevalence of nephrolithiasis has consistently increased over the last 50 years.1 Nephrolithiasis represents a considerable burden for health care systems, with the total health care expenditure for kidney stones exceeding US $10 billion in 2006 in the United States alone.2