Patients with inflammatory bowel disease (IBD), namely ulcerative colitis (UC) and Crohn's disease (CD), have worse outcomes with Clostridium difficile infection (CDI), including increased readmissions, colectomy, and death. Oral vancomycin is recommended for the treatment of severe CDI, while metronidazole is the standard of care for nonsevere infection. We aimed to assess treatment outcomes of CDI in IBD. We conducted a retrospective observational study of inpatients with CDI and IBD from January 2006 through December 2010. CDI severity was assessed using published criteria. Outcomes included readmission for CDI within 30 days and 12 weeks, length of stay, colectomy, and death. A total of 114 patients met inclusion criteria (UC, 62; CD, 52). Thirty-day readmissions were more common among UC than CD patients (24.2% versus 9.6%; P ؍ 0.04). Same-admission colectomy occurred in 27.4% of UC patients and 0% of CD patients (P < 0.01). Severe CDI was more common among UC than CD patients (32.2% versus 19.4%; P ؍ 0.12) but not statistically significant. Two patients died from CDI-associated complications C lostridium difficile causes roughly 20% of antibiotic-associated diarrhea and is responsible for significant morbidity. Its incidence has more than doubled over the past decade (1). Historically, C. difficile infection (CDI) has been associated with such risk factors as antibiotic use, immune suppression and dysfunction, prolonged hospital stays, and advanced age (1-3).Inflammatory bowel disease (IBD) is generally classified as Crohn's disease (CD) or ulcerative colitis (UC), which manifest with intestinal symptoms, including diarrhea and abdominal pain. Patients with IBD are particularly susceptible to the effects of enterocolitic infections, due to underlying alterations in intestinal immunity coupled with often chronic exposure to immunosuppressive therapies. Recent studies have shown that patients with IBD have an increased incidence of developing CDI, with a 2-to 3-fold increase in patients with Crohn's disease and a 4-to 7-fold increase in patients with UC (4-7). Furthermore, patients with underlying IBD who develop CDI experience longer hospital stays and higher rates of colectomy and death than subjects without IBD (5, 8, 9). Consequently, CDI is estimated to have quadrupled the cost of hospitalizations to greater than $1 billion per year relative to matched hospitalizations (1, 10). Several agents have been evaluated for the treatment of CDI, including metronidazole and vancomycin (11).A randomized, controlled trial by Zar et al. demonstrated that vancomycin for the treatment of CDI was associated with improved outcomes in patients meeting criteria for severe CDI, but it conferred no significant advantage over metronidazole for nonsevere disease (12). Notably, patients with IBD were excluded from this trial, and there are no prospective trials comparing antibiotic regimens among patients with CDI and underlying IBD. Largely on the basis of the study by Zar and colleagues, current treatment guidelines rec...