['Potassium citrate is prescribed to patients with calcium oxalate (CaOx) stone formation to increase urinary citrate and pH, thus reducing CaOx crystal formation. Lemonade therapy (LT) might also increase urinary citrate and the total urine volume. We compared the effects of LT alone (group 1, n = 63) and potassium citrate plus LT (group 2, n = 37) in patients with CaOx stone formation on the urinary citrate and total urine volume to determine the efficacy of LT.', 'Adult patients with CaOx stone formation and three or more clinic visits from 1996 to 2005 and three or more UroRisk profiles were included in our retrospective analysis.', 'Urinary citrate increased maximally by 203 and 346 mg/day for groups 1 and 2, respectively. The maximal total urine volume increase was 763 and 860 mL/day for groups 1 and 2, respectively. The urinary citrate and total urine volume increased sooner during follow-up for group 1. By the last clinic visit, the urinary citrate and total urine volume had decreased in both groups. However, group 1 sustained a greater total urine volume than did group 2 (2.35 +/- 0.10 standard error versus 2.17 +/- 0.12 L/day). Urinary citrate was greater in group 1 (765 +/- 56 standard error versus 548 +/- 56 mg/day for group 2), but the change from baseline to the last visit was significant (P = 0.008) only in group 2.'] Does lemonade therapy increase urinary citrate and urine volumes in patients with recurrent calcium oxalate stone formation?