Feeding is a basic behavior that is necessary for life. Long-term lack of food results in death. It is well accepted that appetite is controlled by the brain and that feeding behavior is regulated by complex mechanisms in the central nervous system, in particular the hypothalamus. However, recent identifications of novel neuropeptides and peptide hormones develop a paradigm in appetite regulatory mechanisms in the central nervous system. In this presentation, I will discuss the two appetite-regulating peptides, ghrelin and neuromedin U. Ghrelin is a growth-hormone releasing and appetite-stimulating hormone secreted mainly from stomach. On the other hand, neuromedin U (NMU) is a potent appetite-suppressing peptide. Moreover, we recently revealed that ghrelin directly acts on osteoblast cells to regulate bone formation, and NMU is involved in the regulation of peripheral inflammation. Thus, both ghrelin and NMU are more than appetite regulators, but have multifaceted roles in, for example bone formation and inflammation. [J Physiol Sci. 2006;56 Suppl:S27]