There are no reported head-to-head comparisons of different instillations therapies. Most instillation therapies contain heparin. Heparin is a constituent of the normal glycaso-aminoglycan (GAG) mucosal barrier in the bladder. In patients with IC, this mucosal barrier is thought to be defective, specifically with regard to the presence of heparin. The heparin is thought to "rebuild" the mucosal barrier in the bladder. Many bladder instillation therapies also contain an anesthetic such as lidocaine. The anesthetic is thought to directly treat nerves in and around the bladder through desensitization. Sodium bicarbonate acts to alkinalize the solution which has also been theorized to help with absorption or direct treatment. Lastly, we have found that some patients have had an initial burning sensation for several minutes with the concentrated three ingredient formula and that a small amount of sterile water helps to prevent this. Therefore we add the sterile water to all bladder instillations.