Uric acid is the end product of purine metabolism mainly from the breakdown of nucleic acids and other purine analogues by cellular metabolism and from the enzymatic breakdown of purines in food. The saturation and concentration of uric acid in the body is about 420 μmol/L (7 mg/dl) at 37°C. Above this concentration, hyperuricemia is considered. There are two main causes of high uric acid: increased uric acid production and decreased uric acid excretion, and sometimes both of them coexist. Increased uric acid production: This includes both high purine dietary intake and increased metabolic production of endogenous purines. Food-induced uric acid production is proportional to the purine content of food, and purine-rich foods include animal liver, kidney, anchovies, etc. The increase of endogenous purine metabolism in the body is mainly related to the synthesis and decomposition of purine. Decreased uric acid excretion: About 2/3 of uric acid is excreted through the kidneys, and the remaining 1/3 is excreted through extrarenal pathways such as the intestinal tract and biliary tract. About 90% of patients with persistent hyperuricemia have defects in renal processing of uric acid and show reduced uric acid excretion, including reduced glomerular filtration rate, increased tubular reabsorption, reduced tubular secretion and urate crystallization. In addition, the level of blood uric acid is influenced by multiple factors such as race, diet, region, age, and body surface area. Therefore, special care needs to be taken in the diet to avoid high purine diet. Therefore, high uric acid is mainly caused by two main reasons: increased uric acid production and decreased uric acid excretion.