Transurethral prostatic resection using a 1.5% glycine solution causes a well known clinical and metabolic syndrome called TURP-syndrome. Recent development of percutaneous renal surgery is responsible of several similar accidents. In a prospective study of 150 patients (mean age: 35 +/- 10) subjected to a percutaneous nephrolithotomy, the natremia and the amino acid content of the plasma were measured preoperatively and immediately postoperatively by chromatography. The study shows that there is a post-nephrolithotomy syndrome in two per cent. This syndrome contains a hemodilution with hyponatremia and reabsorption of irrigation fluid. Glycolemia, serinemia and threoninemia increase significantly. These modifications have a good correlation between them except for the natremia. Variability of results in this study and in the literature is explained by difficulty and duration of surgery, volume of glycol used, increasing intrarenal pressures and sudden opening of vessels peroperatively. The gravity of post-nephrolithotomy syndrome requires to change the irrigate solute and use normal saline solution when it is possible.