Carotid angiograms of 33 patients who had died during 1968 and 1969 from blunt head injury were reviewed and assessed for evidence of arterial spasm and slowing of the cerebral circulation. Spasm was found in 57·5%, a prolonged circulation time in 57·5%, and a combination of both features in 42·4% of cases. In the same group of patients there was also a high incidence of ischaemic brain damage. There appeared to be some correlation between arterial spasm and ischaemic damage in the cerebral cortex, but none in the basal ganglia or in the white matter. There was no apparent correlation between a prolonged cerebral circulation time and ischaemic brain damage.