The objective of this study was to review the clinical efficacy of currently available products for the intravesical treatment of bladder pain syndrome (BPS) / interstitial cystitis (IC) and to assess their pharmaco-economic impact. Nineteen articles were reviewed, including five prospective controlled trials. The treatments reviewed in the study were: high molecular weight-hyaluronic acid (HMW-HA) (Cystistat), chondroitin sulphate (ChS) (Uracyst and Gepan), low molecular weight-hyaluronic acid (LMW-HA) (Ialuril), pentosan polysulphate (PPS) (Elmiron) and dimethyl sulfoxide (DMSO). The majority (74%) of these treatments were delivered weekly but all had different lengths of treatment. For most studies the first follow-up was performed at 12 weeks but differing assessment methods were used, although all used a visual analogue score for pain (VAS). This made direct comparison difficult therefore the effect size of VAS reduction was examined in the differing groups. The authors conclude that the review provides evidence of the positive effects of intravesical GAG therapy for PBS/IC and that it may improve patient symptoms significantly. If both medical and pharmacoeconomic aspects are considered then HMW-HA has an advantage over the other instillation agents but a direct comparison between the above agents has not been performed in adequately controlled studies so only limited conclusions can be drawn.