The paper summarizes chemical, physical and physiological qualities of modern perfluorinated carbons. The indications for the application of these artificial oxygentransporting substances in the biological and medical field are summarized and discussed. The characteristics of perfluorocarbons are looked at from historical and current points of view in order to indicate the fields of application and especially the limitations of their applicability. Without any doubt application as a full replacement of blood will be impossible because blood with its multifunctional property cannot be replaced by systems which cover only one or few aspects. Besides this general statement it is also clear that the special qualities of perfluorocarbons make them highly suitable for application in biological and medical fields; their low viscosity allows to improve disturbancies in perfusion. Immunological problems do not occur, and the danger of infection is eliminated compared to biological material. The most important fields of application for perfluorocarbons are the organ perfusion in organ banks for transplantation, the oxygenation of cell cultures and the diagnosis with imaging procedures.