The development of emotional pain stress in rats is accompanied by an increase in lipid peroxidation (LPO) products in the pancreas and a decrease in antiradical activity of its lipids. Hypoinsulinemia, of which a degree of expression is inversely proportional to an increase in peroxidation products, is observed. Antioxidant administration prevents LPO process activation in the pancreas and inhibits, to a great extent, a decrease in the level of insulin in stress. It is assumed that a certain role in the development of hypoinsulinemia in stress can be played by LPO processes resulting in the formation of active forms of oxygen and damage of the islands of Langerhans of B-cells.