The bases of a real metaphylaxis in the renal stone diseases are the analysis of stones and the research of metabolism in blood plasma and urine. The greatest part of the stones analyzed may be classified in four groups: oxalate, phosphate, uric acid and cystine. The metaphylaxis by whewellite and weddellite is the same for both species but there is a distinction in growth and recurrence. In the phosphate stones, the section with the most different composition, a postoperative therapy is only possible with the distinction of 'acid' and 'alkaline' stones. The uric acid and cystine stones need a tight supervision and metaphylaxis for the whole life. On the basis of 15,000 analyses with X-ray diffraction the difference of the renal stones is discussed and the deducation for a genuine metaphylaxis is shown.