the methods by which biomaterials have been and are currently being introduced and accepted into clinical medicine have varied historically and, in part, are dependent upon the device. the materials employed in the vast number of medical devices have long been in common use elsewhere and have simply been used in a different application. the textile and chemical industries have developed synthetics, e. g. nylon, polycarbonate, polyester, polyethylene, polyolefin, polypropylene and a large number of co-polymers. these materials were not synthesized for biomedical applications. early in the history of implantable biomaterials surgeons chose off-the-shelf fabrics and used them as patches or hand sewed the materials into tubes for arterial substitutes. initially, there was no fundamental research into biomaterials. the biologic reactions and ultimate in vivo fate of the materials in the devices were unknown with respect to the influence of residual catalysts, fillers, stabilizers, delustrants, anitoxidants, and oligomer residues. this paper reviews the current methods used for introducing biocompatible materials into medical practice. 12 refs