Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Blood transfusion is the transfer of blood or blood products from a donor into the bloodstream of the recipient. The procedure is performed to replace the blood cells or blood product lost because of severe bleeding or in order to help anemic patients. Although it is a life saving procedure, various social groups oppose to blood transfusion due to personal, religious or medical reasons. Learn more about blood transfusion, its history and possible adverse effects in this book.