OBJECTIVE:To study the chemical constituents of water extract from the root ofAchyranthes bidentataBl.METHODS:To isolate and purify by using silica gel column chromatography the butanol extract of the water extract,to determine the structures by means of IR,MS,1HNMR,13CNMR,1H-1HCOSY,DEPT,and to identify them by chemical analysis and authentic specimens.RESULTS:β-sitosterol,succinic acid,n-butyl-β-D-fructopyranoside,allantoin and magnesium phosphate were elucidated.CONCLUSION:The latter three compounds were first reported in gene Achyranthes.