Hyaluronic acid is a protective barrier of the urothelium. A damaged glycosaminoglycan layer may increase the possibility of bacterial adherence and infection. This damage is proposed to be a causative factor in the development of interstitial cystitis, common urinary tract infections, and hemorrhagic cystitis due to posthematopoietic stem cell transplantation. The aim of this article was to review the available data regarding the use of hyaluronic acid as an alternative treatment of the above-mentioned conditions.Articles relevant to our review that were archived by September 2006 were retrieved from PubMed.Nine relevant studies were identified and evaluated. Hyaluronic acid was administered intravesically at a dose of 40mg every week for 4–6 wk; patients with noted improvement received two additional monthly doses. Short-term responses of patients with interstitial cystitis, hemorrhagic cystitis, and recurrent urinary tract infections were 30–73% (7 studies), 71% (1 study), and 100% (1 study), respectively. The treatment was well tolerated except for occasional development of bacterial cystitis. The cost of each intravesical installation of hyaluronic acid is 120 UK pounds (excluding the cost of the urinary catheterization).The available clinical data regarding the effectiveness of hyaluronic acid as a potential treatment of patients with interstitial cystitis, recurrent urinary tract infections, and hemorrhagic cystitis are limited. There is need for randomized controlled trials for further investigation of this important therapeutics question; these clinical trials should be disease-specific, blinded, and controlled, and of a sufficient number of patients. Until such studies are available, intravesical instillation of hyaluronic acid cannot be unquestionably endorsed for use for the aforementioned diseases.