Thirty-eight patients with problems with their urinary catheters were randomly treated with Varidase or normal saline solution once a day for 10 days. Photographs were taken by using a cystoscope before treatment, at day 10 and day 24 after the commencement of treatment. The photographs were evaluated according to the occurrence of pus, debris, coagula and rubor. In the Varidase group the improvements from baseline to day 10 and day 24 were statistically significant (p less than 0.05) in all parameters while there were no statistically significant improvements in the saline group. Comparing the two treatment groups, regarding the changes from baseline to day 10 and day 24, it was statistically demonstrated that Varidase was significantly more effective than saline in all parameters (p less than 0.05). In conclusion, this study shows that Varidase effectively cleans the urinary bladder from pus, fibrin, necrotic tissue and blood clots.