This is a multi-center, randomized, open label clinical trial, which looks to investigate the efficacy of intravenous iron is in the treatment of preoperative anemia in colorectal patients. Patients will be randomized to receive intravenous ferric carboxymaltose (treatment group) or oral ferrous sulphate (control). The outcomes reviewed will include the amount and frequency of blood transfusions received, changes in patient blood profiles, patient quality of life scores, operative complications and hospital length of stay. The role of hepcidin as a biomarker of treatment response will also be assessed.