Abstract
A 29-year-old man with severe ulcerative colitis and gastroduodenitis was initially treated with oral mesalamine and high-dose intravenous steroid therapy; however, his epigastralgia and vomiting did not improve. After initiating infliximab, the patient experienced prompt improvement in symptoms and inflammation. Although steroids were effective for the colon, they proved ineffective for gastroduodenal lesions, highlighting the necessity for molecular-targeted agents, such as infliximab, in these cases. The timing for administering such agents should be carefully considered.