The literature search included English-language trials identified by using MEDLINE, the Cochrane Database of Systematic Reviews (January 1948 to September 2012), Google Scholar, ClinicalTrials.gov, and Web of Science. The literature search was updated in March 2014, and no additional studies met the inclusion or exclusion criteria. Dietary interventions that were evaluated included intake of fluids, calcium, animal protein, sodium, fruit and fiber, purine, oxalate, potassium, soft drinks, citrus, or multicomponent diets. We also included empirical dietary interventions and those tailored according to patient demographics, comorbid conditions, baseline diet, baseline urine or blood biochemical testing, and/or stone type. Pharmacologic agents evaluated include medications approved by the U.S. Food and Drug Administration and available in the United States for prescription (for example, hydrochlorothiazide, chlorthalidone, indapamide, potassium citrate, potassium–magnesium citrate, sodium citrate, allopurinol, magnesium hydroxide, or acetohydroxamic acid [AHA]). For key questions 1, 2, 4, and 6, we considered final clinical health outcomes as the most important measures of treatment benefit, including symptomatic stone recurrence, pain, urinary tract obstruction with acute renal failure, infection, morbidity related to treatment of a recurrent stone, emergency department visits or hospitalizations for treatment of recurrent stones (for example, for renal colic or acute renal failure), quality of life (general or urologic), and end-stage renal disease. The next most important measures of treatment considered for key questions 1, 2, 4, and 6 were intermediate stone outcomes, including composite recurrence (combination of symptomatic or radiographically detected recurrence), recurrence detected only by scheduled radiographic imaging, and change in stone size. Evidence suggests that stones identified with imaging are associated with symptomatic recurrence. For key questions 3 and 5, adverse effects included any reported by eligible trials (for example, nausea, diarrhea, hypokalemia, weight change, hyperlipidemia, and hyperglycemia). Measures of treatment adherence were those reported by the individual trials (for example, self-report questionnaire, pill count, or as estimated by follow-up urine biochemical measures). Further details about the methods and inclusion and exclusion criteria applied in the evidence review are available in the full Agency for Healthcare Research and Quality report (6).