Introduction. Chronic pyelonephritis is the most common kidney disease. In accordance with the chronic nature of the infection, an important aspect of the treatment of recurrent uncomplicated urinary tract infections is antibiotic resistance. 

The aim of this work is to evaluate dynamics of the number of relapses and severity of symptoms of chronic pyelonephritis against the background of the complex drug «Nephrobac»®. 

Materials and methods. The study included 60 patients aged 24 to 56 years with complaints of pain in the lumbar area, fever, and dysuria. Based on the examination, the patients were diagnosed with chronic pyelonephritis. The patients were randomized into two groups: the first group received only antibacterial therapy, the second group received antibacterial therapy in combination with the biologically active complex «Nephrobac»® 1 capsule 2 times a day for 1 month. Patients of both groups were observed for 6 months from the start of therapy. 

Results. Fewer cases of leukocyturia were observed in the group receiving the antibiotic in combination with «Nephrobac»®, 45% and 75% after 3 and 6 months, respectively. In addition, in the same group, there were significantly fewer patients with bacteriuria after 3 visits in the main group compared with the control group receiving antibiotic therapy. There were no relapses registered 6 months after the start of the study in the group receiving combination therapy, including «Nephrobac»®, there were three patients with 1 relapse each in the control group. 

Conclusions. «Nephrobac»® can be recommended as a part of the complex therapy of chronic pyelonephritis, which has an anti-relapse and anti-inflammatory effect, enhancing antibiotics.