THE RESULTS of decades of research are now coming to fruition with the commercial availability of skin substitutes in this country and throughout the world. In 1998, a human skin equivalent (HSE) (Apligraf; Organogenesis Inc, Canton, Mass) consisting of a bilayered skin construct of type 1 bovine collagen and live allogeneic human skin fibroblasts and keratinocytes was approved in the United States for the treatment of venous ulcers based on the data from a multicenter trial.1