For acute severe colitis (ASC) patients, corticosteroids (CS) was recommended as the first-line treatment in the guideline, but patients have a great risk of requiring colectomy or turning to second-line treatment. This study aim to verify the effectiveness of ulcerative colitis endoscopic index of severity(UCEIS) in predicting the reaction to corticosteroids, and explores the possibility that noninvasive marker fecal calprotectin (FC) could act as an alternative to UCEIS.