Recent advances in our understanding of the asymmetric distribution of lipids across nervous system membranes coupled with the application of biophysical techniques to examine transbilayer structure and function have led to the formulation of a new hypothesis. The author hopes that the insights presented herein will stimulate investigation into this developing new field. The theory provides an approach to correlation the accumulation of nervous tissue membrane peroxidative and cross-linking damage, the loss of transbilayer lipid asymmetry, and loss of transbilayer neuroendocrine, transport, secretory and immunoregulatory functions. Central to this scheme is the role of membrane lipid asymmetry in regulation to and/or coupling of transbilayer functions.