Ghrelin is mainly expressed in the stomach, followed by lower parts of the gastrointestinal tract, Ghrelin secretion is mainly influenced by changes in energy balance and glucose homeostasis, followed by alterations of endocrine axes. Ghrelin therefore seems to be an interface between energy homeostasis, glucose metabolism and physiological processes regulated by the classical endocrine axes that e.g., control growth. Ghrelin most likely defends fat mass to ensure survival and to provide the calories that are needed for growth hormone to act on growth and repair. The possibility of using a ghrelin antagonist for the treatment of obesity initiated a hunt for such a valuable agent. It will not be long before antagonists are disclosed and tested for the treatment of obesity.