Clinical decision support systems (CDSSs) have been hailed for their potential to reduce medical errors and improve the quality and safety of health care. CDSSs aim to assist clinicians in their decision making and take over some routines including diagnostic support. This paper presents a design of a generic medical platform to assist clinicians in their clinical reasoning process. Our platform aims to guide clinicians in the process of gathering relevant information and to help them in their decision making. It exploits two sources of knowledge namely: theoretical knowledge (clinical rules) and practical knowledge (clinical experiences) by relying on Rule-Based Reasoning and Case-Based Reasoning, respectively. moreover , we utilize the semantic web and ontologies for knowledge modeling in order to reuse and to share knowledge.