Vesicoureteral reflux (VUR) is the backward flow of urine from the bladder into the kidneys.

Normally, urine flows from the kidneys through the ureters to the bladder, and the muscles of the bladder and ureters and the pressure of urine in the bladder prevent urine from flowing backward through the ureters. VUR allows bacteria, which may be present in the urine in the bladder, to reach the kidneys. This can lead to kidney infection, scarring, and damage.

The goal of treatment for vesicoureteral reflux is to prevent kidney damage. Treatment may include antibiotics or surgery. Frequent urine tests may be needed to check for infection.