This paper will describe the project, its aims, methodology, and will explore the issues raised by the project, both cultural and process. The project is funded by the European Commission and is led by the Trimbos Institute, Holland, with partners from the UK (DrugScope) and Portugal (Instituto da Droga e da Toxicodependência). The information for the EELDA database is collected and appraised using protocols for Evidence Based Medicine. The development of EELDA content is systematic, structured, and includes a number of safeguards to achieve a high level of quality regarding the final output. Specialised authors and librarians are involved in this process. Within this context, the paper explores the issues raised by working across different cultures, specialists and languages. The paper will also look at the need for evidence based work and reflect on its relevance to substance abuse work, drawing on other examples from France, and North America.