Clinical outcomes of patients with remitting ulcerative colitis after discontinuation of indigo naturalis oleh Fumie Shimada, Yusuke Yoshimatsu, Tomohisa Sujino, Tomohiro Fukuda, Yasuhiro Aoki, Yukie Hayashi, Anna Tojo, Takaaki Kawaguchi, Hiroki Kiyohara, Shinya Sugimoto, Kosaku Nanki, Yohei Mikami, Kentaro Miyamoto, Kaoru Takabayashi, Naoki Hosoe, Motohiko Kato, Haruhiko Ogata, Makoto Naganuma, Takanori Kanai