This study explores the distribution of international, regional and national scientific output in health information and communication, indexed in the MEDLINE and LILACS databases, between 1996 and 2005. A selection of articles was based on the hierarchical structure of Information Science in MeSH vocabulary. Four specific domains were determined: health information, medical informatics, scientific communications on healthcare and healthcare communications. The variables analyzed were: most-covered subjects and journals, author affiliation and publication countries and languages, in both databases. The Information Science category is represented in nearly 5% of MEDLINE and LILACS articles. The four domains under analysis showed a relative annual increase in MEDLINE. The Medical Informatics domain showed the highest number of records in MEDLINE, representing about half of all indexed articles. The importance of Information Science as a whole is more visible in publications from developed countries and the findings indicate the predominance of the United States, with significant growth in scientific output from China and South Korea and, to a lesser extent, Brazil.