Endothelin (ET) is a novel vasoactive peptide occurring in 3 isoforms (ET1, ET2, ET3) in humans. Derived from vascular endothelium cells, ET arises from a precursor peptide and exerts diverse actions through specific receptors. ET possess a wide spectrum of activities: a potent vasoconstrictor activity but also contraction of nonvascular smooth muscles (air-way, intestinal, urinary) or mitogenic actions, renal and endocrine effects. The physiological and/or physiopathological roles of endothelin is still unclear, but ET may play a part in the genesis of some vascular diseases as atherosclerosis, forms of hypertension or may be implicated in the pathogenesis of vasospasm.