Objective To study the chemical constituents of whole plant of Phyllanthus urinaria and their biological activity.Methods The chemical constituents were isolated and purified by repeated column chromatography over silica gel,Rp-C;(reverse phase),MCI,and Sephadex LH-20,as well as semi-preparative HPLC.NMR spectroscopic analyses were used for the structure identification.In this case,the inhibitory rate of NO production of the isolated triterpenoids was evaluated.Results Seven triterpenoids,identified as28-norlup-20(29)-ene-3,17β-diol(1),betulin(2),β-betulinic acid(3),3-oxofriedelan-28-oic acid(4),oleanolic acid(5),3R-E-coumaroyltaraxerol(6),and 3R-Zcoumaroyltaraxerol(7),were isolated and identified from the whole plants of P.urinaria.Compounds 1-5 exerted inhibitory effects against NO production in LPS-induced RAW264.7 mouse macrophages with the inhibitory rate of NO production ranging from 4.0%to 27.8%at the concentration of 25 μmol/L.Conclusion To the best of our knowledge,this is the first report of compounds 1-4,6,and 7 from the family Euphorbiaceae.Compounds 1-5 exhibited inhibitory effects against NO production in LPS-induced RAW264.7 mouse macrophages.