How long does it take for a mild hydronephrosis to heal generally depends on the cause of the hydronephrosis and the patient’s personal constitution and whether the treatment is active or not, so specific analysis is needed. If mild hydronephrosis is caused by acute pyelonephritis, patients need antibiotic treatment and the hydronephrosis can usually disappear on its own after the infection is controlled, about 14 days, depending on the individual. In the case of mild hydronephrosis caused by stones, the hydronephrosis may disappear after the stones are discharged. Patients need to be examined to clarify the size of the stone. Generally, small stones can be discharged by drinking more water, eating more vegetables and fruits, and doing more exercise, etc. If the stones are large, extracorporeal shock wave lithotripsy or surgical lithotripsy is needed. Chinese medicine can be taken during the recovery period. Patients with mild hydronephrosis should pay attention to drink more water, mainly plain water, and urinate regularly to ensure that the daily urine volume is more than 2500 ml. Avoid prolonged sitting and holding urine in daily life, and avoid spicy and stimulating diet.