Urinary stones are a highly prevalent disease in an essentially healthy population, and their composition is often complex. How to prevent the disease of stones and how to prevent the regeneration of stones after treatment is critical. In this article, we briefly explain the methods of prevention of several common types of stones: 1. Prevention of calcium-containing urinary stones Preventive measures for patients with calcium-containing urinary stones should start with changing lifestyle habits and adjusting dietary structure. Maintaining an appropriate body mass index, appropriate physical activity, maintaining nutritional balance and increasing the intake of citric acid-rich fruits are important measures to prevent stone recurrence. Only when changing lifestyle habits and adjusting dietary structure are ineffective, medication should be considered. (1) Increase fluid intake: Increasing fluid intake increases urine volume, thus reducing the supersaturation of urinary stone components and preventing stone recurrence. The recommended daily fluid intake is 2.5 to 3.0L or more, so that the daily urine volume is maintained at 2.0 to 2.5L or more. Regarding the type of water to drink, non-dairy fluids with low oxalic acid content are generally considered to be appropriate. Excessive consumption of caffeine, black tea, grape juice, apple juice and Coca-Cola should be avoided. It is recommended to drink more orange juice, sour fruit vine juice and lemon water. (2) Dietary modifications: Maintain a comprehensive nutritional balance in the diet, emphasizing the avoidance of excessive intake of one of the nutrients. A low-calcium diet can reduce urinary calcium excretion but may lead to osteoporosis and increased urinary oxalic acid excretion. Eating a diet with normal calcium content and limiting animal protein and sodium intake has a better effect on preventing stone recurrence than a traditional low-calcium diet. Foods such as dairy products (milk, cheese, yogurt, etc.), tofu and small fish are recommended. The daily intake of calcium for adults should be 800-1000mg (20-25mmol). Limit the intake of oxalic acid in the diet: The excretion of oxalic acid in the urine increases significantly after a large intake of foods rich in oxalic acid. Patients with calcium oxalate stones, especially those with hyperoxaluria, should avoid oxalic acid-rich foods such as kale, almonds, peanuts, beets, parsley, spinach, rhubarb, black tea, and cocoa powder. Among them, the content of oxalic acid in spinach is the highest, and patients with calcium oxalate stones should pay more attention to avoid eating spinach. (3) Limit sodium intake: A high-sodium diet increases urinary calcium excretion. (4) Limit excessive protein intake: A low-carbohydrate and high-animal protein diet is associated with the formation of calcium-containing stones. A high protein diet causes increased urinary calcium and urinary oxalate excretion while decreasing urinary citrate excretion and lowering urinary pH, which is one of the important risk factors for the formation of calcium-containing stones in the urinary tract. It is recommended to consume a nutritionally balanced diet, and it is important to maintain a balanced diet of 3 meals: breakfast, lunch and dinner. Avoid excessive intake of animal protein, which should be limited to 150g per day. Among them, patients with recurrent stones should not consume more than 80g of protein per day. (5) Reduce body weight: Studies have shown that being overweight is one of the crucial factors in the formation of urinary tract stones. Increase the intake of fruits and vegetables: The intake of fruits and vegetables in the diet dilutes the lithogenic risk factors in the urine, but does not affect the concentration of urinary potassium and urinary citrate. Therefore, increasing the intake of fruits and vegetables may prevent stone recurrence in patients with hypocitraturia. Increase coarse grains and fiber diet: rice bran can reduce urinary calcium excretion and decrease the recurrence of urinary stones, but avoid oxalic acid-rich fiber foods such as wheat bran. (6) Reduce the intake of vitamin C: vitamin C can produce oxalic acid after natural transformation. The excretion of urinary oxalic acid increases significantly with vitamin C, and the risk of calcium oxalate crystals increases accordingly. It is recommended that patients with recurrent calcium oxalate stones avoid high doses of vitamin C. It is recommended that their daily intake of vitamin C should not exceed 1.0 g. (7) Restrict high purine diet: Patients with calcium oxalate stones with hyperuricemia should avoid a high purine diet and the recommended daily intake of purine in food should be less than 500 mg. Foods rich in purines include: animal offal (liver and kidney), poultry skin, herring with skin, sardines, anchovies, etc. 2.Prevention of uric acid stones The key to prevent uric acid stones is to increase urine volume, improve the pH of urine and reduce the formation and excretion of uric acid in 3 ways. (1) Drink a lot of water: keep the daily urine volume above 2000ml. (2) Alkalinize urine: to maintain urine pH between 6.5 and 6.8, you can give sodium potassium hydrogen citrate (Youlet) 1 to 2g, 3 times/d, potassium citrate 2 to 3g or sodium potassium citrate 3 to 6g, 2 to 3 times/d, or sodium bicarbonate 1.0, 3 times/d. (3) Reduce uric acid formation: for increased blood uric acid or uric acid, take allopurinol 300mg/d orally. Folic acid can inhibit xanthine oxidase activity more effectively than allopurinol. 5mg/d of oral folic acid is recommended. 3. Prevention of infected stones Low calcium and low phosphorus diet is recommended. Aluminum hydroxide or aluminum carbonate gel can combine with phosphorus ions in the small intestine to form insoluble aluminum phosphate, thus reducing the absorption of phosphorus in the intestine and the excretion of urinary phosphorus. For amyl phosphate and carbonate apatite stones caused by bacterial infection with urease, the stones should be removed surgically if possible. The use of antibiotics based on drug sensitivity testing is recommended for the treatment of infections. It is emphasized that anti-infective therapy requires an adequate course of medication. In the initial phase of antibiotic therapy, the dose of antibiotics is relatively high (therapeutic dose), and the urine is made sterile by 1 to 2 weeks of treatment, after which the drug dose can be halved (maintenance dose) and maintained for 3 months. It is important to pay attention to the monthly bacterial culture, if bacteria are found again or the patient has symptoms of urinary tract infection, the drug will be restored to the therapeutic amount to better control the infection. 4. Prevention of cystine stones Pay attention to drink a lot of water to increase the solubility of cystine, ensure that the daily urine volume is more than 3000ml, i.e. drink at least 150ml/h. Alkalize the urine so that the pH of urine reaches more than 7.5. It is advisable to consume a low protein diet based on vegetables and cereals and avoid excessive consumption of foods rich in methionine (soy, wheat, fish, meat, beans and mushrooms, etc.) A low protein diet reduces the excretion of cystine. Limit the intake of sodium salt, the recommended sodium intake is limited to less than 2g/d.