The most common causes of mild hydronephrosis in the right kidney are the following: First, holding urine is too obvious, especially in the urinary tract ultrasound requires holding urine for treatment, and some patients wait for a long time, which can lead to holding urine too obvious and mild hydronephrosis, and then review mild holding urine again, and if hydronephrosis disappears, no special treatment is needed. Second, patients who hold urine for a long time, such as office workers, long-term sedentary hold urine, can cause mild hydronephrosis, it is recommended to drink more water, urinate regularly, avoid long-term sedentary hold urine, you can often do strenuous exercise to promote the discharge of urine, etc. Third, urinary tract infection, especially upper urinary tract infection, can appear the right side of the waist soreness, ultrasound can suggest right hydronephrosis. It needs to apply antibiotic treatment for 10-14 days. Fourth, caused by stones and obstruction, the effusion can be reduced after the stones are discharged.