ObjectivesThe PRASCO trial reported the short‐term superiority of an antibiotic cocktail plus intravenous corticosteroids (IVCS) over IVCS alone in children with acute severe colitis (ASC). Here, we report the extension of the PRASCO trial and the long‐term outcomes of the antibiotic cocktail in ASC.MethodsThis prospective follow‐up of the PRASCO trial documented disease outcomes and treatments annually through 5 years. The primary outcome was colectomy, and the secondary outcome was escalation to biologics, analyzed descriptively.ResultsA total of 26 children were included (12 receiving IVCS and 14 receiving IVCS + antibiotics), 19% of whom underwent colectomy during the follow‐up period. The estimated probability of colectomy at 3, 6, and 12 months from admission were 7.1%, 7.1%, and 21% with IVCS + antibiotics and 0%, 8.3%, and 17% with IVCS. No children required colectomy after the first year of follow‐up. The estimated probability of escalating to biologics were 66%, 77%, and 77% after 1, 2, and 3 years with IVCS + antibiotics and 42%, 51%, and 76% with IVCS. Clinical remission was higher in the IVCS + antibiotics group at each timepoint (e.g., 30% vs. 11% at 5‐years). Delta of Pediatric Ulcerative Colitis Activity Index (PUCAI) score from baseline to day three of admission predicted future escalation to biologics (area under curves (AUC) 0.84 [95%CI 0.59–1.0]).ConclusionWhile adding antibiotics to IVCS may provide better short‐term outcomes, the long‐term benefits were comparable to IVCS alone. At 5 years, about one‐fifth of children had undergone colectomy, and almost four‐fifths had escalated to biologics, particularly during the first year after admission.