 The purpose of this study was to determine the effect of two probiotic preparations Agri-King Synbiotic and Oxadrop on urinary oxalate excretion in patients with mild hyperoxaluria. Probiotics are live microorganisms thought to be beneficial to the host organism. Hyperoxaluria is a hereditary disorder that causes a special kind of stone to form in the kidney and urine. Oxalates are naturally-occurring substances found in plants, animals, and in humans. Excretion of oxalates in the urine is a risk factor for kidney stone formation. 