The aim of the study: to study the effect of mexidol content of ionized calcium and magnesium in erythrocytes and the number of circulating endothelial cells in patients undergoing surgery in the maxillofacial area. Material and methods. The intracellular concentration of calcium and magnesium was measured before the operation, in one, three and five days after the surgery with the help of cytochemical method. Mexidol (100mg) was administered intravenously as a single addition to the standard premedication. Results. After surgery, the intracellular calcium and magnesium content increased. After 24 hours, the magnesium level began to decline, and the calcium content in erythrocytes continued to grow. On day 5, the magnesium concentration in erythrocytes decreased below the initial level, and calcium levels remained significantly elevated. Number of endothelial cells in the blood increased immediately after surgery and magnesium-calcium balance and limits endothelial dysfunction. Mexidol continued growing, reaching a peak on day 5 after surgery. When using mexidol decreased levels of calcium and magnesium levels help prevent falls on the 5th day after surgery, decreased the number of circulating endothelial cells. Conclusion. Mexidol prevents postoperative magnesium violation.