The article presents data on the chemical composition and antioxidant properties of the organs of onion angular (Allium angulosum L.), growing in the Irkutsk region and the Republic of Buryatia. Allium angulosum L. has in its composition biologically active compounds, including those with antioxidant properties, which indicates a high potential and prospects for the use of this plant for food purposes. The aim of the work was to assess the chemical composition and total content of antioxidants in dried samples of leaves and stems of onion angular (Allium angulosum L.), growing in different conditions of the Baikal region. The study of carbon and nitrogen in different plant organs revealed that the carbon content is higher in stems, nitrogen in the leaves in all samples of onion angular, grown in different conditions. It is noted that in the organs of Allium angulosum L., growing on typical cold black earth, the content of the studied elements is higher in comparison with their content in other experimental samples. It was revealed that the stems and leaves of angular onions accumulate in their composition trace elements K, Na, Li, Mg, Ca. The study of the total content of antioxidants indicated that leaf extracts have in their composition more antioxidants than stems, regardless of the place of growth. The high content of antioxidants in Allium angulosum L. provides inhibition of oxidative processes in the storage of pork fat, which introduced crushed dried leaves of Allium angulosum L.