Sanofi S.A.is a French multinational pharmaceutical company headquartered in Paris, France, as of 2013 the world's fifth-largest by prescription sales. Originally, the company was established in 1973 and merged with Synthélabo in 1999 to form Sanofi-Synthélabo. In 2004, Sanofi-Synthélabo merged with Aventis and renamed to Sanofi-Aventis, which were each the product of several previous mergers. It changed its name back to Sanofi in May 2011.
Sanofi engages in the research and development, manufacturing and marketing of pharmaceutical drugs principally in the prescription market, but the firm also develops over-the-counter medication. The company covers seven major therapeutic areas: cardiovascular, central nervous system, diabetes, internal medicine, oncology, thrombosis and vaccines (it is the world's largest producer of the latter through its subsidiary Sanofi Pasteur).