  We consider the propagation and damping of isovector excitations in heated
nuclear matter within the Landau Fermi-liquid theory. Results obtained for
nuclear matter are applied to calculate the Giant Dipole Resonance (GDR) at
finite temperature in heavy spherical nuclei within Steinwedel and Jensen
model.
  The centroid energy of the GDR slightly decreases with increasing temperature
and the width increases as $T^2$ for temperatures $T < 5$ MeV in agreement with
recent experimental data for GDR in $^{208}$Pb and $^{120}$Sn.
  The validity of the method for other Fermi fluids is finally suggested.
