The response of nuclei to spin-isospin excitation which is displayed through heavy ion induced charge-exchange reactions, is concentrated in two excita- tion energy domains. At low excitation energy, several particle-hole states contribute : the Gamow-Teller resonance and higher multipolarity spin-flip resonances. Around 300 MeV, a nucleon from the target is excited to a Δ resonance. On an average, the strength in the Δ sector has the same order of magnitude as in the nuclear sector. In detail, the Δ excitation strength depends on the nuclear structure of the projectile-ejectile pair. The peak corresponding to Δ excitation in nuclei is energy shifted from the peak of the free Δ created in the reaction on hydrogen.