Inflammatory bowel disease (IBD) is a chronic inflammatory condition for gastrointestinal tract. There have been numerous studies to reveal dysbiosis of fecal/mucosal microbiome composition in IBD patients but actual trend of dysbiosis is strikingly different among patient's ethnicity. In this background, the investigators have composed a prospective cohort of Korean IBD patients in a large academic referral IBD center. Using an integrated multi-omics bioinformatic analysis, the investigators aim to explore gut microbial signatures along with distinct clinical/genetic features, and their potential interplay in patients with IBD.