Uric acid is the end product of purine metabolism and is mainly produced by the enzymatic breakdown of nucleic acids and other purine analogues from cellular metabolism and purines from food. Adult enzymatic serum (plasma) uric acid concentrations range from 150 to 416 μmol/L for men and 89 to 357 μmol/L for women, approaching that of men after menopause. A lower than normal uric acid concentration is considered low blood uric acid. The liver is the main site of uric acid production, except for a small portion of uric acid that can be further broken down in the liver or excreted with bile, the rest is excreted from the kidneys. Uric acid can be excreted freely through the glomerulus and also through the renal tubules, but about 90% of uric acid entering the primary urine is reabsorbed back into the blood in the renal tubules. Therefore, the causes of low uric acid are mainly the impairment of renal tubular reabsorption of uric acid due to various reasons, the loss of large amounts of uric acid in the urine, and the reduction of uric acid production due to severe impairment of liver function. For example, acute hepatic necrosis, hepatomegaly, etc. In addition, chronic cadmium poisoning, use of sulfonamide and high dose glucocorticoids, congenital defects in xanthine oxidase and purine nucleotidase, which are involved in uric acid production, can also cause a decrease in blood uric acid. Therefore, there are two main reasons for low uric acid: firstly, reduced uric acid production due to severe impairment of liver function, and secondly, reduced reabsorption of uric acid by the renal tubules. The specific cause of low uric acid in patients should be combined with the patient’s medical history and related tests to confirm the final diagnosis.