Electric light scattering by aqueous ferric oxide suspension (beta-FeOOH) is investigated as a function of the concentration and degree of hydrolysis of polyacrylamide (HPAM), The kilohertz electro-optical effect (alpha(s)) connected with ion polarization in the diffuse part of electric double layers of particles decreases with increasing HPAM concentration, It falls to zero near to the isoelectric point of particles and increases again after surface recharging to a value that does not change with further polymer concentration increase. alpha(s) is shown to be independent of HPAM charge density in stabilized suspensions, In contrast, the variations of the low frequency effect (at hertz frequencies) after the isoelectric point of particles correlate well with the charge of macromolecules. Similarity between the frequency behavior of the electro-optical effect in stabilized suspensions and the dielectric dispersion of polyelectrolyte solutions is noted. The hydrodynamic thickness of the adsorbed layer, obtained from electric light scattering, is found to be independent of the charge of macromolecules in stabilized suspensions. Its value (L(r) similar to 10 nm) is 5-6 times smaller than the thickness of the adsorbed uncharged polyacrylamide, indicating a flatter conformation of the adsorbed polyelectrolyte molecules.