The treatment of interstitial cystitis is difficult and at time frustrating--both for the patient and for the physician. Treatment is hampered by the lack of a clear understanding of its pathophysiology, which makes it difficult to objectively assess disease severity and/or progression. Intravesical therapy appears to be the most successful approach to the relief of symptoms. Clearly, there are drawbacks to intravesical therapy, particularly Clorpactin lavage. Responses to intravesical lavage are variable in duration, unpredictable, and unamenable to objective measurement. Multiple treatments are frequently needed, as with DMSO, and multiple anesthetics may be required for Clorpactin therapy. There have been no double-blind, placebo-controlled studies comparing the mainstays--Clorpactin and DMSO--of intravesical treatment. It is hoped that current research into the pathogenesis and causation of interstitial cystitis will lead to an improved understanding of this disease or syndrome. The introduction of newer, more specific intravesical therapies will surely follow such advances.