Acute severe ulcerative colitis (ASUC) is a severe exacerbation of ulcerative colitis (UC) disease activity, characterized by clinical symptoms of bloody diarrhoea and abdominal discomfort accompanied by features of systemic inflammation, such as elevated C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) levels.1 Here, CRP is linked to ulcerative colitis.