The pathophysiological analysis of cerebral hemodynamic mechanisms and its metabolism in the vegetative patients was not enough until now. It was reported in this paper that the correlation between cerebral hemodynamics, metabolism and neurological function was analysed in 14 patients with vegetative state caused by cerebrovascular disorders. The materials consist of 14 vegetative patients due to 7 hypertensive intracerebral hemorrhage, 6 subarachnoid hemorrhage and one cerebral infarction. In all of them, the cerebral hemodynamics such as cerebral blood flow (CBF), CO2 reactivity and autoregulation, and cerebral metabolism were measured sequencially by 133Xe clearance methods. In the majority of cases, both values of mean hemispheric CBF and cerebral oxygen consumption (CMRO2) were markedly decreased with severe impairments of autoregulation and CO2 reactivity on the bilateral hemispheres but much more significatly on the affected hemispheres. Futhermore, from view points of the pressureflow relationship in the CBF studies, the patterns of dysautoregulation could be classified into 2 types as follows; Type 1 is the complete loss type, which has no plateau formation in all ranging of systemic arterial blood pressure (SABP). Type 2 is the incomplete loss type with 2 subdivisions, in which the abnormal narrowing plateaus are recognized in relatively higher or lower range of SABP (called as the upper or the lower type of incomplete loss type respectively). And then, the phenomen, which we gave a term as "shift-off phenomenon", was recognized in 8 cases that the proper values of resting SABP was seated outside the plateau level of the auto-regulatory capacity. The correlation between CBF dynamics and the grade of vegetative state was analysed. In 2 cases with slight communications (vegetative grade1), mean hemispheric CBF value was 32.5 (ml/100 g/min.) and CMRO2 was 2.01 (ml/100 g/min.) with the normal or the upper type in incomplete loss of dysautoregulation. In 3 cases of vegetative grade 2, who could slightly response to vocal order, mean CBF and CMRO2 showed 27.0 +/- 2.0 and 1.7 +/- 0.08 respectively. In these cases, dysautoregulations with the upper type incomplete loss were recognized. In 3 cases of vegetative grade 3, who had only spontaneous movement of body and slight emotional expression but no response to vocal order, mean CBF was in 22.4 +/- 1.9 and CMRO2 in 1.28 +/- 0.21. The patterns of dysautoregulation showed the lower type of incomplete loss. We had experienced the shift-off phenomenon in all of 5 cases with the upper type of incomplete loss and in 3 of 7 cases with the lower type of incomplete loss dysautoregulation. As conclusion, in cases of vegetative grade 2 or 3 whose patterns of dysautoregulation are the upper or lower type of incomplete loss with the shift-off pnenomenon, it would be a useful therapeutic method to get away from vegetative state that SABP could be corrected and controlled within the proper plateau level of autoregulation by the suitable administration of some vasoactive agents.