This article reviews a recently d is covered new peptide-growth hormone-releasing peptide: ghrelin. Ghrelin is secr eted by various tissues of body, mainly by gastric tissue. Ghrelin regulates GH release from pituitary, participates in the regulation of energy metabolism, inh ibits the proliferation of tumor cells and influences the cardiovascular functio n and the release of other hormones. The study of ghrelin in many fields is prel iminary and needs further investigation.