Since feeding behavior has a complex physiological background, in the physiology of feeding behavoir not only the mechanisms in the hypothalamus, but also input and output physiologic factors which stimulate and/or inhibit the central network for feeding and aversion behavior, must be considered. Normal feeding and aversion behavior are accomplished by a series of highly co-ordinated physiological functions involving various parts of the body, and humoral, hormonal, metabolic, and sensory and motor functions for feeding behavior must be well considered from a wider wiew point. For this purpose, morphological, biochemical, and neurophysiological extensive approaches to study the feeding behavior mechanisms are essentially important. In the present paper, neurophysiological network concerning feeding and aversion behavior was under discussion. Particularly, relations between input, central and output factors for these behaviors were considered. As an input factor, a role of the nerve impulses of the chorda tympani and lingual nerves was evaluated. As a central factor, involvement of the neurons in the cortical taste area was discussed, and response patterns of cortical taste neurons to negative and positive taste information was analyzed with regard to taste perception mechanisms. In addition, mechanisms in the posterior hypothalamus for the taste aversion behavior were explained through ablation and recording techniques in the rat; and the neuromuscular mechanisms of chewing, which complete the feeding behavior, were also discussed. Importance of such comprehensive systematic approach to proper understanding of feeding and aversion behaviors was emphasized.