Ghrelin is a 28 aminoacids peptide secreted from the stomach that stimulates the release of growth hormone (GH) from the anterior pituitary cells and is the strongest orexigenic hormone discovered so far. Ghrelin seems to be involved in the pathogenesis of obesity, anorexia nervosa and cachexia. Furthermore, low levels of ghrelin are negatively correlated with the degree of insulin resistance, blood pressure and the prevalence of type 2 diabetes. The role of ghrelin in the energy homeostasis and carbohydrate metabolism is discussed.