Acute severe ulcerative colitis (ASUC) is a potentially life-threatening condition that requires early recognition, hospitalization and adequate treatment. Currently, the use of infliximab in ulcerative colitis (UC) is recommended in the case of severe disease refractory to corticosteroids, once that superimposed bacterial or viral infections (such as cytomegalovirus or Clostridium difficile) have been excluded. However, conventional weight-based regimens of infliximab might be insufficient for patients with ASUC. Accelerated infliximab induction regimen may increase its serum concentration levels and efficacy by reducing early colectomy rates in these patients. We report a 34 year old female presenting with an ASUC. She was initially treated with hydrocortisone 300 mg/day and mesalazine enemas 4g/day with an unfavorable clinical response. At the fifth day of therapy, an accelerated induction therapy with infliximab was started in doses of 10 mg/kg at weeks 0, 1 and 4. After the second dose, there was a favorable response with reduction of abdominal pain, stool frequency and hematochezia. She was discharged with prednisone and azathioprine. After four weeks of starting infliximab, the patient remains in clinical remission.Acute severe ulcerative colitis (ASUC) is a potentially life-threatening condition that requires early recognition, hospitalization and adequate treatment. Currently, the use of infliximab in ulcerative colitis (UC) is recommended in the case of severe disease refractory to corticosteroids, once that superimposed bacterial or viral infections (such as cytomegalovirus or Clostridium difficile) have been excluded. However, conventional weight-based regimens of infliximab might be insufficient for patients with ASUC. Accelerated infliximab induction regimen may increase its serum concentration levels and efficacy by reducing early colectomy rates in these patients. We report a 34 year old female presenting with an ASUC. She was initially treated with hydrocortisone 300 mg/day and mesalazine enemas 4g/day with an unfavorable clinical response. At the fifth day of therapy, an accelerated induction therapy with infliximab was started in doses of 10 mg/kg at weeks 0, 1 and 4. After the second dose, there was a favorable response with reduction of abdominal pain, stool frequency and hematochezia. She was discharged with prednisone and azathioprine. After four weeks of starting infliximab, the patient remains in clinical remission.