One commonly encountered problem in clinical urology is how to treat patients with calcium stone disease in a long-term perspective. At least ten per cent of the population in most parts of the world are afflicted by stone formation of which calcium stones undoubtedly dominate. The clinical problem comes from the fact that the disease is associated with a considerable recurrence rate. During a 10-year follow-up period recurrent stone formation can be expected in about half of the patients. In a Swedish epidemiological study it was shown that 30 per cent of patients who presented with their first stone had formed one or more new stones after 10 years. For those who had a history of more than one stone at the start of follow-up, the corresponding recurrence rate was 70 per cent (1). There is thus an obvious reason to provide some form of recurrence prevention at least to patients with the most severe course of the disease. Although several therapeutic alternatives today are available for such a purpose, their clinical efficacy is far from that desired. There are several explanations for our therapeutic shortcomings, but one important factor is our incomplete understanding of exactly how calcium stones form. Such knowledge is an absolute prerequisite for designing a rational effective and dynamic recurrence preventive treatment.