In this paper, we deal with a blood supply chain management problem. We focus in particular on blood distribution routes design and optimization. Blood is a scarce and perishable product, made of multiple components, each with specific compatibility rules. We would like to investigate the impact of com-patible products substitution and transshipment between hospitals on blood de-mand satisfaction. We use the case of the blood supply chain in Belgium as an application. We model the case as an Inventory Routing Problem with transship-ment and substitution for perishable products in a capacity constrained environ-ment. We implement the model and conduct experimentations to evaluate the contribution of both transshipment and substitution with regards to shortages and distribution and inventory costs reduction. In a capacity constrained environ-ment, at equivalent cost, mismatching/substitution is preferred to transshipment to satisfy the demand and avoid backorders.