Background Inflammatory bowel disease (IBD) exacerbation requiring hospitalization increases the risk of venous thromboembolism (VTE), and current guidelines recommend pharmacologic VTE prophylaxis (PVTEP). Aims Bleeding risks with PVTEP in this population are poorly defined, and no study has investigated packed red blood cell (PRBC) transfusion requirements in this population. Methods We conducted a chart review of all adult hospitalizations for IBD exacerbation within the Northwell Healthcare system. Patient characteristics recorded included demographics, disease type ulcerative colitis or Crohn's disease, severe disease defined by inpatient corticosteroid or biologic use, and admission hemoglobin. Inpatient use of PVTEP and antiplatelet therapies were identified. The primary outcome was the occurrence of any packed red blood cell (PRBC) transfusion. Results In total, 717 patients met inclusion criteria, accounting for 891 admissions. PVTEP was used during 60.4% of admissions, and 11.1% of patient admissions included a transfusion event. Severe disease patients receiving PVTEP had an 18.6% transfusion risk, versus 11.1% for those not receiving PVTEP, OR 1.82, CI (1.04-3.17). One multivariable analysis transfusion was associated with PVTEP, OR 2.11, 95% CI 1.18, 3.77, p=0.0120, disease severity OR 3.17, 95% CI 1.81,5.54, p<0.0001, anti-platelet therapies OR 2.46, 95% CI 1.23-4.90, p=0.0107, bowel resection OR 3.88, 95% CI 1.97,7.63, p<0.0001 and decreased admission hemoglobin OR 2.01, 95% CI 1.73-2.32, p<0.0001, but not disease type ulcerative colitis OR 0.71, 95% CI 0.42-1.20. Conclusion PVTEP during IBD exacerbation is associated with increased PRBC transfusions. Our findings do not constitute a contraindication to PVTEP, but may be incorporated into patient counseling during inpatient IBD management.