GIN Austria (Gesundheitsinformationsnetz Austria) offers patients and consumers reliable medical knowledge about diseases, wellness and disease management in an easy understandable way and enables them to quick and incessant access to informations about the Austrian health system and Austrian health organizations. To achieve full customer (patients, citizens) satisfaction to find relevant information we propose a concept of a vector-model oriented IR-Tool based on the controlled vocabulary of the MeSH Thesaurus (german version). By this approach users who are often not used to scientific terms and expressions are supported to build up their own query with MeSH Main Headings. In a second step broader and narrower Main Headings are added to the query vector by the system. For this calculation an adapted version of the Floyd-Warshall algorithm for directed, azyclic graphs is used. The tool is part of the GIN Search Modul, which will ease gathering health information from different heterogenous internet datasources.