We exposed erythrocytes in soluble hemoglobin and Fe
^{+2}
, in which hydroxyl radical (OH
\bm{\cdot}
) might be generated, and measured low shear rate viscosity and viscoelasticity of erythrocyte suspensions at Hct of 40%. The quantities of the lipid peroxidation product, malonyldialdehyde (MDA), for oxidized samples were higher than that for control (e.g., 2.20
\pm
0.46 nmol and 1.70
\pm
0.42 nmol,
n={}
6,
p={}
0.01, respectively). The viscosity values of oxidized erythrocyte suspensions for all tested shear rates were higher than those for the control samples (
p<{}
0.05 or better,
n={}
6). Dynamic viscosity (
\eta'
) of oxidized erythrocyte samples was higher than that of control samples at the tested shear stress of 30 mPa whereas it was not observed in elasticity values (
\eta''
). We tentatively concluded from the study, that oxidized erythrocytes would be more prone to form aggregates and increase viscosity of blood at low shear rates. Therefore, they might impair blood flow in the microcirculation.
