The development of kidney stones (Nephrolithiasis) is a widespread disease, associated with painful episodes, hospitalizations and, not neglectable, surgical interventions. The causes of stone formation are low fluid intake, too few vegetables and fruits (citrates), too much oxalate and animal proteins and excessive salt intake. All of these boosters should be counteracted so that the mineral concentrations in the urine can be reduced and any crystallization prevented.

Approximately 80–90% of the kidney stones contain calcium in different salt forms. The increased urinary excretion of calcium, oxalate and low citrate are the most striking features of these patients. Kidney stones occur more frequent in western countries. The recurrence rates after the first episode of stone formation increase strongly from 40% within the first 5 years to 50% within 10 years and over 75% within 20 years. Therefore it is very important to prevent these relapses, because each episode of a stone formation is harmful to the kidneys.