The present study was performed to evaluate the ability of Lactobacillus probiotics to reduce the urinary oxalate excretion level and prevent recurrent pyelonephritis. Methods. The open, 6 months randomized controlled trial was followed up. 80 women with recurrent pyelonephritis, caused by E. coli or S. faecalis, were randomly allocated into 2 groups. The 1st Group (n = 40) took Symbiform® which contained acidophilic and plantar Lactobacilli, Lactococci (lactis and cremoris), Bifidobacteria (adolescentis and bifidum) and thermophilic non–pathogenic Streptococcus. The 2nd one (n = 40) received oxalate–soluble herbal remedy Uronefron® containing 188 mg of city extract from 9 plants. Probiotic was prescribed in a dose of 1 sachet 2 times a day during the first 5 days, followed by a dose reduction of 1 sachet per day for a month. Uronefron® was prescribed in a dose of 3 pills a day for a month. Results. 1 month after the end of the treatment, microbiological studies of the colon microflora demonstrated the increasing level of Lactobacillus spp. colonization more than 7 million CPU/1 g of faeces: 35/40 (87.5 %) in the patients of the 1st Group vs 6/40 (15 %) in the women of the comparison Group f/f = 41.5; p < 0.0001). The levels of daily urinary oxalate excretion were significantly decreased in both groups: the patients of Probiotic Group: 117.6 ± 11.7 vs 71.9 ± 10.07mg/d after the treatment (p < 0.0001) and 122.02 ± 17 vs 84.8 ± 9.8 mg/d (p < 0.0001) in the women of the 2nd Group, respectively. In the 6 months preceding randomization, at least 1 recurrence of pyelonephritis occurred in 2/40 (5 %) women of the Probiotic Group and 9/40 (22.5 %) in the patients of Group II (//= 5,1; p = 0,02). Conclusions. The use of lactobacillus probiotics in non–stone fanners women with recurrent pyelonephritis increases the quantitative content of Lactobacillus spp. in the gut, reduces daily urinary oxalate excretion and the number of pyelonephritis recurrences.