Anemia is common in inflammatory bowel disease (IBD), with a prevalence ranging 
from 8.8% to 73.7%. This wide range reflects the definitions used and the 
populations studied. Although many patients are reported to be asymptomatic, 
systematic studies have shown anemia to have a significant impact on quality of 
life. Consequently treatment should be instituted early. The commonest cause of 
anemia in IBD is iron deficiency, predominantly related to gastrointestinal 
blood loss. Anemia of chronic disease often occurs concomitantly, due to 
cytokine-mediated impaired erythropoiesis and dysregulated iron metabolism. Oral 
iron is a simple and effective method for treating iron deficiency, but requires 
long courses of treatment. It is also theoretically implicated with worsening 
intestinal inflammation, via the production of toxic reactive oxygen species. 
Intravenous iron avoids these concerns, especially with the development of 
ferric carboxymaltose, which allow up to 1000mg to be given rapidly. In patients 
failing to respond to intravenous iron, the anemia of chronic disease is most 
likely to be causative. In this setting evidence suggests that additional 
erythropoietin therapy can be effective. Blood transfusions should be avoided as 
part of routine management and reserved for patients with substantial acute 
gastro-intestinal bleeding, where there is a risk of hemodynamic compromise. 
This article discusses the underlying physiology of anemia in IBD, and presents 
the current evidence supporting treatment options available.