The most important component of urinary tract stones is calcium oxalate, which accounts for about 87.5% of urinary tract stone patients in China. In the food containing the highest oxalate is spinach, research has proved: if you eat 200 grams of spinach, urinary excretion of oxalic acid will be significantly higher, especially in 2-4 hours after eating to reach a peak, 8 hours later is still higher than the level before eating, than those who did not eat spinach increased oxalic acid 20-25 mg, the study also found that eating fried spinach than eating hot spinach in the urinary excretion of oxalic acid high. If there is too much oxalate in the food and the urine is oversaturated with calcium oxalate, the extra calcium oxalate crystals may be precipitated from the urine to form stone crystals, and if the crystals are not excreted in time with the urine, more and more crystals will be formed and gradually aggregated to form kidney stones.