The object of the present invention relates to sulfated hyaluronic acid (HAS) for topical use in the prevention and/or treatment of skin pathologies associated with damage to the endothelium and/or the wall of blood vessels, in the treatment of clots of fibrin and thrombi which are formed at the skin level; as a skin absorption promoter of pharmacologically and/or biologically active agents and in the prevention and/or treatment of Herpes Simplex labialis and Herpes genitalis, the virus of Vesicular Stomatitis and Cytomegalovirus.