Nutrition is therefore an important indicator in diagnostics and the basis for successful prophylaxis, because its components can influence the composition of urine. Patients with calcium oxalate stones should avoid foods with a high oxalic acid content (e.g., spinach, chard, rhubarb, nuts, cocoa). Foods rich in energy, protein and purine, as well as frequent alcohol consumption, also promote the formation of uric acid stones. Meat lovers should therefore pay attention to a balanced diet with lots of vegetables, fruit and cereal products, and have plenty to drink. Only when the urine is sufficiently diluted can the sometimes troublesome stones be avoided. 2.5 to 3 litres a day should be enough. Beverages that do not influence urinary pH levels are best. These include kidney and bladder teas, as well as fruit and herbal teas, some fruit juices such as diluted apple or grape juice, and mineral waters low in calcium and hydrogen carbonate.