This is a multicenter, randomized, double-blind, placebo-controlled, parallel-design, exploratory study of orally administered ERB-041 in subjects with active IC. The primary objectives of this study will be to investigate ERB-041’s activity on levels of urinary APF, explore the gene expression response in peripheral blood mononuclear cells (PBMC), and to evaluate the safety of ERB-041 in women with active IC.