The condition of hydronephrosis can be mild or severe, depending on the degree of hydronephrosis, the duration of hydronephrosis, and whether there is bilateral hydronephrosis. Severe hydronephrosis may affect the function of the entire kidney, resulting in decreased kidney function and affecting the health of the body. There are many causes of hydronephrosis, such as congenital hydronephrosis, and hydronephrosis caused by ureteral stones, in addition, like some urological tumor diseases, may also cause hydronephrosis. If the urinary tract is not smooth and the urine cannot be excreted smoothly due to stones and tumors, unilateral mild hydronephrosis, the patient’s kidneys will not be affected much if the obstruction is removed in time. If the hydronephrosis is bilateral and persists, it is more serious and may cause kidney failure and eventually lead to uremia. If the hydronephrosis is caused by stones, you should eat less food with high oxalic acid content, such as spinach or some bamboo shoot vegetables, to prevent the stones from growing or recurring after treatment, leading to progression or recurrence of the disease.