Mild fluid retention in the left kidney will not be cured by itself, and the cause of fluid retention needs to be clarified and treated according to the doctor’s instruction before it can be cured. There are many reasons for mild fluid retention in the left kidney, so it is necessary to complete the relevant examinations to identify the cause and then give the corresponding treatment. If the hydronephrosis is only caused by common urinary stones or kidney stones, it can be treated by physical therapy, i.e. extracorporeal lithotripsy. However, if it is a urinary tract infection, such as pyelonephritis, it needs to be treated with antibiotics, and the treatment cycle may be longer, about one month, and the recurrence is also higher. In addition, be sure to drink more water to promote urination, which is also helpful in treating left hydronephrosis. If the development of left hydronephrosis is more serious, it may affect the kidney function, so you should pay special attention to it in daily life, and you can eat foods such as black sesame to improve it and try to avoid the progress of the disease.