there is a growing realization that healthcare is a knowledge-intensive field. the ability to capture and leverage semantics via inference or query processing is crucial for supporting the various required processes in both primary (e.g. disease diagnosis) and long term care (e.g. predictive and preventive diagnosis). given the wide canvas and the relatively frequent knowledge changes that occur in this area, we need to take advantage of the new trends in semantic web technologies. in particular, the power of ontologies allows us to share medical research and provide suitable support to physician's practices. there is also a need to integrate these technologies within the currently used healthcare practices. in particular the use of semantic web technologies is highly demanded within the clinicians' differential diagnosis process and the clinical pathways disease management procedures as well as to aid the predictive/preventative measures used by healthcare professionals.