The paper studies experimentally the antioxidant activity of onion peel acetone extracts of three varieties (Albion F1, Kaba, Red Baron) in the inhibition process of polyethylene thermal oxidation. The onion varieties differ in the color of their surface scales (colorless (white onion), yellow-orange (yellow onion), red (red onion)) and in the antioxidant properties of their extracts: red onion> yellow onion >> white onion. The results correspond to the mass of the extracted substances. A different sequence of onion varieties has been obtained in terms of the inhibitory effectiveness of their extracts: yellow onion> red onion >> white onion. The comparison of the extracted onion peel extracts with the industrial antioxidant Irganox 1010 in terms of inhibitory efficiency has been carried out. The paper presents and analyzes the IR spectra of the extracts. An increase in the extraction time from 24 hours to 56 days leads to an increase in the antioxidant properties of the extracts of all three varieties, but an increase in the inhibition efficiency is noted only for Albion F1 onion peel extract. In Red Baron and Kaba varieties, the main part of biologically active substances with antioxidant action is extracted from the peel into acetone during the first days of extraction.