The hypolipidemic activity of chitosan nanopowder prepared by ultrafine milling

► The hypolipidemic activities of two chitosan nanopowders were studied in rats. ► Chitosan nanopowder showed better hypolipidemic activity than ordinary chitosan. ► The 51.4-kDa nanopowder was superior to 315.2-kDa nanopowder in hypolipidemic activity. ► The hypolipidemic mechanism of chitosan nanopowder was studied.