Medical Affairs is a link between the scientific and marketing units of a pharmaceutical company. Medical writers in this field are responsible for writing varied document types from regulatory reports to scientific publications, and marketing supports. Sources of medical information include scientific literature, pharmaceutical company internal data, and regulatory guidelines. For each of these documents, the final reader is different. Consequently, the key message and writing style should be identified and adapted accordingly. The medical writer has a responsibility to ensure that the right medical information is relayed to the target reader.