Extraction　and　purification　of　polyphenolic　compounds　from　Hsian-tsao　(Mesona　procumbens　Hemsl.)　were　investigated.　The　polyphenolic　compounds　were　extracted　by　using　acetone,　ethanol　or　methanol　at　three　different　concentrations.　The　polyphenolic　concentration　and　the　inhibition　of　lipid　peroxidation　were　determined.　The　results　showed　that,　among　solvents　tested,　75%　acetone　solvent　extracted　a　maximum　amount　of　polyphenolic　compounds　from　Hsian-tsao.　The　75%　acetone　extract　was　purified　further　by　AB-8　adsorption　column　chromatography　and　eight　fractions,　A　similar　to　H,　were　obtained.　Among　eight　fractions,　Fraction　E　had　the　highest　polyphenolic　content　and　inhibition(76%).　Moreover,　Fraction　E　was　separated　into　four　polyphenolic　compounds　(1　similar　to　4)　by　HPLC　and　each　compound　reached　a　purity　of　more　than　98%.　The　structure　of　the　compound　was　identified　by　LC-MS　and　NMR,　and　the　compound-4　was　determined　to　be　astragalin　(a　flavonol　glycoside)　which　was　obtained　from　HT　for　the　first　time.