The problem of free radical pathologies in high temperatures in animal husbandry and veterinary medicine is extremely important scientific and practical. In the process of hyperthermia, the structure of cell membranes, the permeability of membranes, and membrane transport systems change, which cause the oxidation of unsaturated fatty acids and the accumulation of toxic products of a radical nature. This plays an important role in the development of many pathological conditions. The review article describes the problem of the influence of heat stress (HS) on a living organism and the problem of hyperthermia in animal husbandry. Emphasis is placed on the role of the body's antioxidant system in a state of HS and the use of antioxidant drugs as additives into feed for farm animals, aimed at mitigating the course and harmful effects in HS. On the one hand, our goal was to describe in an accessible form the main complex biochemical disorders in the body under HS conditions, which lead to a deterioration in the welfare and loss of productivity of animals. On the other hand, we tried to show the special role of the antioxidant defense system in preventing the development of oxidative stress in its classical representation. Also, we substantiated the choice in favor of using natural and synthetic antioxidants as one of the strategies for the prevention of HS in modern animal husbandry.