In the course of prolit treatment there was a spontaneous evacuation of small concrements from renal calyces and ureters in 11 (27.5%) patients, dilution of the concrements and reduction in size of the latter were observed in prolit combination with blemaren (2 patients--5% and 7 patients--17.5%, respectively). Overall response was 50% while that to cyston--16.7%. Diuretic, anti-inflammatory and plastic actions of prolit manifested in 100% patients with disappearance of salts from urinary sediment, abatement of microhematuria and mild leukocyturia. Thus, prolit is a highly effective food additive in the treatment of nephrolithiasis and opens new perspectives in the treatment of urolithiasis.