Self-medication, defined as the act to treat oneself with or without drugs, is a common practice in industrial countries. A study of available computerized solutions in this field highlights that this issue has not been considered with enough attention, although they provide valuable services to both patients and health care organizations. This paper presents XIMSA, a self-medication knowledge-based system, which is supported by a database/ ontology collaboration. This collaboration is guaranteed by DBOM, an application-independent system which enables the end-user to design, enrich and maintain an ontology from an existing database. DBOM's functionalities are presented within XIMSA's application domain.