Pfizer Canada operates the largest pharmaceutical company in that country. Pfizer has a mission to discover, develop and manufacture innovative medications that will improve the health and peace of mind for people all over the planet. The well-known company, Pfizer Canada is one of the foremost investors in Canadian research and development. In 2005, Pfizer Canada invested more than $190 million dollars in medical research. Viagra is currently a best seller in Canada as well as other parts of the world. Pfizer manufactures it and men with ED thank them for it.