The increase in fibrinogen level is consequent on several hurtful events: inflammatory, traumatic, stress reaction. Traumatic event, during cerebral vasculopathies, often causes an inflammatory reaction, certainly in the acute phase, inducing fibrinogen synthesis. There are also other inflammatory changes as the increase in WBC and PLT counts and in other hematic components, both in increase and in decrease. Patients with cerebral vasculopathies were divided in two groups according to the clinic picture seriousness. Haemorheologic characteristics were measured with a double filtering method I (with 5 and 12 mu filters) and under a filtering pressure of 15 cm H2O, eliminating WBC interference even if using native blood. In this way we have determined whole blood, plasma, and plasma-erythrocyte viscosities. From these measures we have obtained corpuscular viscosity and erythrocyte deformability. Fibrinogen concentration is increased in all patients with acute vasculopathies, but there is not a difference in relation to the clinic pictures seriousness. Also other inflammatory parameters, namely: total protein, gamma-globulins, ESR, are increased in a significant way without difference in relation the clinic seriousness. The WBC count is more increased in the group with Stroke than in the other one with TIA. The corpuscular viscosity is almost doubled with consequent decrease in deformability; plasma-erythrocyte viscosity, measured with both methods, is quite increased. These parameters show the same behaviour in both groups. Only plasma viscosity increased in the group with Stroke. Haemorheology alteration is not statistically correlated to the fibrinogen level. The decrease in deformability can be related to the viscouselastic membrane properties, and the fibrinogen, because of its adhesive properties, can contribute to such a decrease.