In 40 patients with umcomplicated hypertension their general haemodynamics was compared with the excretion of catecholamines and their metabolites. On the initial stage of the disease the hormonal link was found to prevail over the mediator one; the decreasing excretion of bound catecholamines after the administration of Isuprel indicates that a disbalance between the secretion and inactivation of catecholamines develops as early as on this stage of the disease. Later, in resistance hypertension the administration if Isuprel resulted in an increased excretion of free noradrenalin, which is interpreted as a sign of increased reactivity of this link; no such reaction is noted in ejection hypertension. A study of all these links of the sympathoadrenal system is important for the understanding of the pathogenesis of hypertension and for the choice of this therapy.