 Specific Aims are: 1 Determine the effect of two probiotic preparations AKSB and Oxadrop on urinary oxalate excretion in a well-defined group of patients with enteric hyperoxaluria; and 2 Determine the effect of two probiotic preparations AKSB and Oxadrop on urinary oxalate excretion in a well-defined group of patients with idiopathic calcium oxalate urolithiasis and mild hyperoxaluria. If results are positive, treatment for calcium oxalate kidney stones could be revolutionized. 