The qualitative and quantitative analysis of phenolic acids was carried out using methods of HPLC with the diode array detector (DAD). The quantitative analysis of chosen phenolic acids was carried out using the Multicomponent Analysis method (MCA). Solid-phase extraction was applied for the purification of crude extract from aerial part of three species of fam.Asteraceae(Chrysanthemum maximumRam.(DC),Chrysanthemum segetumL.,Rudbeckia laciniataL.). The choice of optimal conditions of analysis was made using DryLab+ software.