Sixteen patients dying after subarachnoid haemorrhage (SAH) were investigated with regard to the presence of angiographic vasoconstriction and of glycosaminoglycans in samples from the main cerebral arteries. All patients had a statistically significant (p less than 0.001) vasoconstriction at angiography performed before death. At morphological examination, the vessels of all patients showed signs of intimal thickening, necrosis of the media and leucocyte infiltration of the adventita. The presence of glycosaminoglycans was determined semiquantitatively and did not differ from the values obtained from presumably normal controls. It is suggested that the angiographically verified vasoconstriction found after SAH as well as the morphological changes of the cerebral arteries are not related to a concentration increase of glycosaminoglycans.