Of 59 patients with chronic calculous pyelonephritis (CCP) taking preparation therapy for extracorporeal lithotripsy, 29 patients received combined basic treatment (antibacterial drugs, phytotherapy, physiotherapy) plus polyoxidonium (a course of 10 intramuscular 6 mg injections each other day). The rest 30 patients (controls) received basic therapy alone. Polyoxidonium efficacy was assessed by the results of clinical, device and immunological investigations, content of the main phospholipid fractions and cholesterol in red cell membranes. The results of the tests show that polyoxidonium has anti-inflammatory and immunomodulating effects, exhibits activity of peroxidation processes, contributes to normalization of a lipid phase of cell membranes and can be recommended as a component of combined treatment of patients with chronic pyelonephritis and urolithiasis.