This article presents the isolation, quantification and antioxidant evaluation of bioactive principles from Epimedium elatum. LC-MS guided isolation technique was applied for the separation of target constituents. Three isolates; magnoflorine, chrysin and dibenzylideneacetone (DBA) were isolated for the first time from E. elatum using LC-MS guided isolation method. Nine natural products, viz. icariin, epimedoside A, epimedin A, epimedin B, epimedin C, ikarisoside C, baohuoside II, magnoflorine and chrysin were simultaneously quantified by reverse phase HPLC-UV-DAD method. The HPLC method was validated in terms of precision and accuracy. Excellent specificity and linearity within test ranges for all standard calibration curves having regression coefficient of different linear equations in the range of 0.9966-0.9999 were observed. Relative recovery rates varied between 98.09±0.44 and 105.34±1.89% with relative standard deviation of less than 3%. This modified HPLC method is in accordance with yinyanghuo. All the 10 isolated constituents were screened for DPPH radical scavenging activity. Dibenzylideneacetone (DBA) turned out to be the most potent isolate with IC(50) of 4.32 μM.