An alternative method for assessing the quality of sea buckthorn oils and extracts from the concentration of biologically active lipid substances exhibiting antioxidant activity is considered. The method of microcalorimetry is used to assess the content of antioxidants. The heat of a model cumene oxidation reaction in the presence of sea buckthorn oils and extracts obtained by various technologies is registered. As compared to other methods for obtaining sea buckthorn lipid fractions, the extraction of sea buckthorn fruits with sunflower oil is considered to be an unproductive method, since an increase in antioxidant activity compared with the initial oil is found to be moderate: from 1.56∙10-3 to 1.69∙10-3 mol/kg. Sea buckthorn oil obtained by pressing berries (antioxidant content 6.12∙10-3 mol/kg) and carbon dioxide extraction of sea buckthorn meal (antioxidant content 5.92∙10-3 mol/kg) are of the highest biological value among the objects under study. The maximum amount of antioxidants (5.5∙10-2 mol/kg) is determined in a dry extract of sea-buckthorn fruits enriched with triterpenic acids of the ursan and olean series. The method for assessing the quality of extracts used in the work allows choosing the most efficient technique for processing sea buckthorn fruits. The concentration of antioxidants consisting of a complex of tocopherols, carotenoids, triterpenoids, lipophilic acids, and other compounds is a good criterion of the quality and therapeutic value of oils.