Abstract It has been long since French physician Jean-Baptiste Denys carried out the first successful blood transfusion to a human being. Using bird feathers as canules, sheep blood was transfused to a young man. The patient died soon after Denys' treatment and Denys was accused of murder. In the XXI
century, known as the biotechnology century, we face new challenges in Medicine. New emerging and reemerging diseases, such as Creutzfeldt-Jakob disease (CJD) or "mad cow disease" and its human variant (vCJD), challenge the biosafety aspects of a widely extended and extremely usefu technique, that is, the perfusion of blood, of its derived components and of other pharmacological products obtained from plasma. To face these new challenges we need innovative preventio strategies.