Extraintestinal complications are common in IBD, and are reported in more than 25% of patients. Anemia is one of the most common manifestations of IBD. One-third of patients with IBD have hemoglobin levels below 12 g/dL. Although ongoing blood loss from chronically inflamed intestinal mucosa and micronutrient deficiency (iron and B12) are the main mechanisms underlying the development of anemia in patients with IBD, chronic inflammation, hemolysis, and medication-induced myelosuppression may also play important roles.