OBJECTIVES Assess the impacts of the preventive treatment of patients suffering from recurring cystitis by means of a standard dry cranberry extract. METHODS An observational, longitudinal and prospective assessment by Urologists as part of their professional everyday activity. RESULTS Ninety-two female patients, with an average age of 53.9-18.9 years, were included in the study. These patients had been monitored for a period of 7 months (median). Before inclusion, 89 of the patients (96.7%) had been offered an antibiotherapy. Depending on the patients, the factors that triggered their cystitis most frequently were: sexual relations (58.0%), alcohol consumption (27.6%) and diarrhoea (19.3%). The frequency and urgency of urination, the burning sensation upon urination, the inability to completely empty the bladder and sensation of heaviness in the pubic region were the five symptoms assessed every three weeks. On inclusion, the scores for each symptom were, respectively: 6.2; 6.5; 6.1; 3.1 and 4.6. The overall score was 28.9. After 3 months, the scores for each symptom were, respectively: 1.6; 1.9; 1.9; 0.4 and 0.7. The overall score was 7.1. The evolution of the overall score (p<0.001) was significant, as was that of each respective symptom. The prevalence of cystitis at 3 months was 47.6% (versus 96.7%) on inclusion. CONCLUSIONS The prevalence of urinary problems in subjects suffering from recurring cystitis was halved after 3 months of treatment by means of a standard dry cranberry extract (96.7% versus 47.6%).