The causes of kidney stone formation include the following: One reason is the increased amount of stone-forming components in the urine. Various factors that cause an increase in the concentration of salts, uric acid, oxalates, and cystine in the urine can exceed their solubility. This results in the precipitation and crystallization from the urine, which further grows into stones. For example, hyperuricemia can lead to an increased excretion of urinary uric acid, making it easy to form urate stones. Secondly, the reduction in urine substances that inhibit stone formation, including decreases in citrate and magnesium, can promote stone formation. Third, urinary tract obstruction and infection can lead to stone formation. In cases of urinary tract obstruction and poor urine flow, small crystals formed in the urine can easily adhere to the epithelial cells of the urinary tract, becoming the nucleus of the stone. Urinary tract obstruction may also lead to urinary tract infections where bacteria, pus, and damaged, necrotic epithelial cells can also form the core of stones and gradually develop into larger stones. Fourth, diet and hydration play significant roles. Long-term, high intake of high-protein, high-sodium, high-sugar foods can cause increased excretion of urinary calcium and uric acid, while reducing citrate levels, thus promoting stone formation. A decrease in water intake can also cause urine concentration, further promoting stone formation. Fifth, environmental factors and genetic factors are considered to be related to the formation of kidney stones. It is believed that the hardness of water and genetic factors also have certain relationships with kidney stone formation.