We will investigate the safety and effectiveness of a mixture of 9 east Indian herbs known as Cystone regarding their ability to dissolve existing kidney stones and prevent formation of new ones. Cystine and calcium stone formers will be recruited for a 59 week trial. The first phase of the study will be two 6 weeks periods during which each subject will receive Cystone or placebo in random order (with a one-week wash out between 6 week treatment periods). The remaining 46 weeks, each subject will receive Cystone. End points are changes in urinary chemistries and stone burden by Computerized Tomography (CT) scanning.