The existence of different vocabularies in the pharmaceuticals supply chain hinders collaboration and information sharing between partners (suppliers, delegations, hospitals ...). Also, it generates risks and errors that can prevent the access to pharmaceutical products in hospital facilities. For the supply system of medicines in public hospitals in Morocco, ontology is a solution that will improve understanding between actors, promoting information dissemination and their exploitation and promote a new approach to designing information systems. However, implementation of such an approach requires close collaboration between the various partners and requires an intensive exchange of data between them. These technical data must be transmitted, interpreted, managed, reused and stored in a consistent and standardized way. In this work, we developed an ontology using the OWLGRed tool from a UML model whose objective is risk management in the medicines supply chain in Morocco, principally in the public hospitals that supply itself in a centralized way through the supply division which handles the purchase, storage and distribution of pharmaceuticals in these institutions.