Ghrelin is a hormone produced by endocrine cells in the stomach. Ghrelin stimulates the secretion of growth hormone by the anterior pituitary. This effect is mediated by hypothalamic growth-hormone secretagogue receptors. Binding to these receptors not only stimulates growth hormone secretion, but also has vascular effects (positive inotropic effects), modifies (decreases) insulin sensitivity, affects glucose metabolism (hyperglycaemia) and stimulates gastric-acid production. Antiproliferative effects of ghrelin have been described on experimental tumour models. Ghrelin seems to play a role in stimulating the appetite as well as promoting a more effective storage of food components. Whether or not ghrelin could play any role in the induction of weight gain has yet to be established. This is also true for the role of potential ghrelin antagonists in the induction of weight loss in case of obesity.