Introduction. Urinary tract infections are the second most common type of bacterial infections worldwide. Treatment of patients with chronic (recurrent) cystitis remains challenging and requires an individual approach.Aim. To assess the efficacy of combined therapy for exacerbation of chronic cystitis.Materials and methods. A total of 65 women aged 18–48 years were enrolled in an open comparative bidirectional study. All participants received antibacterial therapy for exacerbation of chronic cystitis in accordance with the clinical guidelines for the treatment of cystitis in women. After the therapy was completed, the comparison group (35 patients) did not receive any drugs, whereas 30 patients from the treatment group were prescribed Cystenium II biologically active dietary supplement at a dose of 1 orally disintegrating tablet twice daily for 2 weeks. The examination included a measurement of the severity of complaints using the Acute Cystitis Symptom Score (ACSS), a clinical urinalysis and urine culture + sensitivity test. The efficacy of treatment was assessed following completion of antibiotic therapy and two weeks after the therapy.Results. After finishing antibiotic treatment, no patient has achieved full recovery (improvement of urinalyses, no growth of pathogenic microbial flora, no complaints). Both groups showed statistically significant decreases in ACSS scores on Visit 2. Over the following two weeks, the symptoms in the comparison group did not change (p > 0.05), and in the treatment group the sum of scores continued to decrease, reaching an average of 3.62 ± 0.42, which is 5.5 times less than the baseline level and almost 3 times less than the sum of scores following completion of antibacterial therapy (p < 0.05). The positive changes in leukocyturia and bacteriuria were also more pronounced in the treatment group.Conclusion. After completion of antibiotic therapy for relapse of chronic (recurrent) cystitis, the patients usually have residual effects that cannot be regarded as presentations of an active disease, but they disturb patients. A two-week course of pathogenetic therapy with a combination drug containing A-type Vaccinium macrocarpon proanthocyanidins, vitamin C and D-mannose to be received as the second step can increase the efficacy of treatment.