The purpose of the study was to investigate the dynamics of acute phase reactants concentrations in the blood changes of patients with subarachnoid haemorrhage in the earliest period of illness. The investigation was carried out in 20 patients with subarachnoid haemorrhage. The total sialic acid, haptoglobin and ceruloplasmin level in the blood of patients with subarachnoid haemorrhage was statistically significantly higher than in the control group.