The article provides a comparative analysis of data on the content of macro-and micronutrients, as well as the determination and identification of biologically active substances in the bioextracts obtained with distilled water (BE-I) and 70% ethanol (BE-II) from the shell of the common hazelnut (Corylus avellana L.) plant widespread in the northwestern region of Azerbaijan. It was established that the bioextracts BE-I and BE-II have the same mineral composition and contain 25 mineral elements. The bioextracts obtained by extraction with distilled water and 70% ethanol contain 28.51% and 14.61% mineral elements respectively. The amount of macronutrients (K, Na, Mg, Ca, Fe, P) in BE-I is 22.97%, micronutrients (Ti, Cr, Mn, Ni, Cu, Zn, Ga, Zr, Sn, Sr, Y, Al, S, Se, Si, Ba, Pb, Rb, V)-5.54%; in BE-II 11.60% and 3.01%, respectively. It was established that the BE-II contains 85.4% biologically active substances (BAS) and 28 major therapeutic substances, while the BE-I contains 71.5% BAS and 14 major therapeutic substances. Phenolic compounds with high antioxidant, anticancer and antibacterial properties were found among the BAS, of which the following components dominate: 2-methoxy phenol (C7H8O2), 2,3-dihydrobenzofuran (C8H8O), 2-methoxy-4-vinylphenol (C9H10O 2) , 4-Hydroxy-3-methoxybenzaldehyde (C8H8O3), 2-methoxy-4-propyl-phenol (C10H14O2), 4-((1E)-3-hydroxy-1-propenyl)-2-methoxyphenol (C10H12O3), dibuthyl phtalate (C16H22O4), 1-naphtalenamin (C10H9N), 5-cholestene-ol, 24-methyl-(C28H48O), γ-sitosterol və β-sitosterol (C29H50O), stiqmast-4-en-3-one (C29H48O), 4H-pyran-4-one-, 2,3-dihydro-3,5-dihydroxy-6-methyl-(C6H8O4), trans-4-fluoro-4'-(methyltio) chalcone (C16H13FOS). The bioextracts obtained by the proposed methods contain vital macro-and microelements and BAS with high therapeutic effect, which allows them to be used as a therapeutic agents in the treatment and prevention of many diseases. Based on the results of the study for obtaining bioextracts rich in mineral elements, BAS, coloring pigments and flavorings the optimal regime was determined using two-stage extraction by 70% ethanol and distilled water.