Methods and compositions useful for the treatment and prophylaxis of calcium renal stones are disclosed. The methods involve administering potassium citrate compositions to persons afflicted with or susceptible to calcium renal stone formations. A typical dosage scheme involves administering about 30 to 120 meq potassium citrate per day in divided doses. Such treatments are effective in dissolving existing calcium stones and preventing formation of new calcium stones. Moreover, the results of a comparative clinical assay indicate the potassium citrate is superior to sodium citrate in the treatment of uric acid lithiasis. Potassium citrate therapy averts calcium renal stone formation, a complication which is often associated with sodium citrate or sodium bicarbonate alkalinization therapy.