The aim of this prospective study was to investigate the effect of extracorporeal shock wave lithotripsy (SWL) on kidneys of patients with pyelic stone disease. The effects of SWL were assessed by high-resolution proton nuclear magnetic resonance (HNMR) spectroscopy of urine samples.Twenty-three patients, aged 31-80years (mean: 55years), with pyelic stone disease were investigated before and after SWL. Multiparameter analysis was performed by HNMR spectroscopy of urine samples collected before and 5h after SWL (second miction post-SWL).The most relevant resonances determined by HNMR spectroscopy were acetate, lactate, trimethylamine N-oxide and amino acids. Excretion of these markers increased significantly in comparison with pre-SWL urinary samples.These results show that early ischemic damage occurs after SWL. Post-SWL. HNMR spectroscopy is an effective tool for noninvasive follow-up of renal damage.