Methods. In the experiment, 30 white mature rats were divided into 5 groups: Group 1 — control, Group 2 and Group 3 — rats exposed to tartrazine at the rate of 750 and 1500 mg/kg for 60 days. In the Group 4 and Group 5, mexidol was injected intramuscularly at the rate of 50 mg/kg against the background of the conditions of the Group 2 and Group 3. Electron microscopic examination of the adrenal glands was performed according to the standard protocol. Results. In the Group 2, epithelial cells of the glomerular and fascicular zones have a round or oval nucleus with uneven contours. The nucleus contains accumulations of heterochromatin under the karyolemma and in the karyoplasm. Large mitochondria with vesicular cristae are observed in the cytoplasm. The cisterns of the smooth endoplasmic reticulum are poorly developed. Lipid inclusions are located in groups or singly. In the Group 3, mitochondria with partially destroyed cristae were detected in the cytoplasm of endocrinocytes of the zona glomerulosa, and in the epithelial cells of the zona fasciculata, loosely packed lamellar structures were detected in the center or periphery of mitochondria, as well as cells with apoptosis. Endocrinocytes of the zona reticularis have a small size, an oval nucleus with slightly tortuous contours and accumulations of heterochromatin in the karyoplasm in the rats of the Group 2. Mitochondria were large and medium in size with spherical cristae in cross section, the cisterns of the smooth endoplasmic reticulum are unevenly expanded and fill the gaps between mitochondria. In the Group 3, almost half of the large mitochondria have densely packed lamellar structures along the periphery or in the center. Conclusion. The above-established ultramicroscopic features of endocrinocytes of the adrenal cortex after 60 days of exposure to tartrazine indicate a decrease in their secretory activity, which depends on the dose of the supplement administered. The introduction of mexidol against this background helps to restore the disturbed ultramicroscopic picture of cells to control values, which is more pronounced in the Group 4.