Abstract： Background In 2008, infants in some areas of China suffered from stones of the urinary system which were caused by melamine-contaminated milk formula. Most of the infants were asymptomatic, and a few suffered from acute renal failure induced by urinary obstruction by stones. This study aimed to assess the significance of blood purification therapy in treatment of infants with acute obstructive oligo-anuric renal failure. Corrective perception, timely diagnosis, and active treatment of this complex disease are critical factors that guarantee a quick recovery of renal function of infants and help them to prevent multiple organ system failure.Methods Thirteen infants with acute renal failure induced by urinary multiple obstruction caused by melamine-containing stones who had been admitted to Beijing Children's Hospital Affiliated to Capital Medical University in 2008 were investigated for the epidemiological characteristics, image features and indications of dialysis. All these infants were treated with dialysis. The efficacy of dialysis was compared with that of two control groups treated with cystoscopic retrograde catheterization into the ureter and medical treatment for the recovery of renal function.Results The 13 infants with life-threatening complications treated with dialysis showed a blood urea nitrogen (BUN) level of (30.9±7.9) mmol/L and a creatinine (Cr) level of (572+173) pmol/L. Of these infants, 8 were treated with peritoneal dialysis (PD), and 5 with hemodialysis (HD). Ten infants recovered to urinate 24-72 hours after dialysis and 3 infants with persistent ureteral obstruction were further treated with cystoscopic retrograde catheterization into the ureter for drainage, and urination resumed soon after the operation. The average time of PD and HD were (2.1±0.8) days and (1.2±0.4) days, respectively. The total average time of PD and HD dialysis was (1.77±0.83) days. The recovery time of renal function of infants after dialysis was (3.08±1.20) days, comparable to that of the two control groups treated with catheterization with a cystoscope or by medication. There was no significant difference in the recovery time of renal function among the three groups (P>0.05).Conclusions Melamine-contaminated milk formula may cause urinary stones and obstructive acute renal failure in infants. Dialysis is suggested to treat life-threatening complications such as hyperkalemia, oliguria or anuria if surgical intervention fails. If possible, hemodialysis or peritoneal dialysis can be performed early. Blood purification is feasible to help the infants overcome the critical stage of acute renal failure. Surgical measures can be taken to remove the obstruction if necessary.