📕 In the development of principles of adaptation syndrome, and to certain extent as a counter to hypothalamic-pituitary- ortical mechanism of stress of H.Selye, on the basis of results of many years of studies, we made a research work of adrenal-thyroid system, ensuring mechanisms of protecting mechanisms formation and regulation of adaptation processes. The monograph presents these mechanisms of thyroid gland hormones and catecholamines action as structural components of adrenal-thyroid system, in regulation function of mitochondria, bioenergetic processes, immune system, enzymes of purine nucleotides metabolism and antioxidant system and possibility of their use in recovery of processes disrupted by stress. Shown are fundamental mechanisms of interrelations both in adrenal-thyroid system, as well as in regulation and energy metabolism, immunoprotection and other adaptation processes. It was established that mechanisms of deadaptation arising under long or recurrent stresses of any origin to the body are based on disorder of regulatory function of adrenal-thyroid system, and this condition can be qualified as adrenal-thyroid dysfunction syndrome