The role of functional state of hematoencephalic barrier (HEB) was estimated in terms of development of pathological process in coma. The quantitative determination of neurospecific protein (NSP), exactly of alpha 1 and of alpha 2 cerebral globulins (produced by astrocytes and oligodendroglial cells) was used for estimation of HEB state. The clinical examination of 138 children in comatose state caused by different factor (meningitis, encephalitis, cerebrocranial trauma, infectious toxicosis) was performed. Enzyme immuno-assay of alpha 1 and of alpha 2 cerebral globulins allowed to control HEB's functional state objectively in "brain-blood" direction: in cases of alteration of HEB's function the autoantibodies to NSP may penetrate into cerebral tissue and cause nonspecific reaction in form of edema or inflammation. The membrane stabilizing effect of Dexamethazone was established.