The cause of anemia in IBD is multifactorial. The most common cause for anemia in IBD patients is iron deficiency anemia (IDA) secondary to increased blood loss from inflamed gastrointestinal mucosa and impaired absorption of iron. The anemia can be macrocytic due to impaired absorption of other nutrients including folate and cobalamin. Other causes are anemia due to medication (such as sulfasalazine) and anemia of chronic disease (ACD) .