A gradual increase in histamine content with simultaneous elevation in the histaminase activity were observed in many tissues of guinea-pigs and cats in dynamics of tetanic intoxication. A universal accumulation of serotonin at early steps of intoxication with subsequent decrease in its content were also found in development of severe generalized tetanus. At the same time, in several tissues the inhibition of glycolysis and impairment in electrolyte balance were observed. Artificial pulmonary ventilation was accompanied only by partial compensation in impairment of the histamine and electrolytes metabolism. The metabolic impairments studied possess the complex genesis, they are not related solely to the effect of hypoxic factor and may form the basis for impairment in the excitability of various structures, for alteration in their energy provision and for operation in dynamics of tetanic intoxication.