Interstitial cystitis (IC) is a chronic inflammatory condition of the bladder that causes frequent, urgent, and painful urination and pelvic discomfort. The natural lining of the bladder (epithelium) is protected from toxins in the urine by a layer of protein called glycoaminoglycan (GAG). In IC this protective layer has broken down, allowing toxins to irritate the bladder wall. The bladder then becomes inflamed and tender and does not store urine well.