To determine whether COX-2 activity alters the susceptibility of C3H/HeN mice to severe acute, chronic and recurrent cystitis, we pretreated C3H/HeN mice orally with a non-selective COX inhibitor (indomethacin), a COX-2 specific inhibitor (SC-236), or a COX-1 specific inhibitor (SC-560). This evidence concerns the gene PTGS2 and chronic cystitis.