The adsorption behaviors of Alizarins and Reactive blue X-BR on both activated carbon covered with colloidal silver were studied using the surface-enhanced Raman scattering (SERS). The adsorptive mechanisms of both Alizarins and Reactive blue X-BR were discussed. The results indicated that colloidal silver can greatly enhance Raman scattering responses and colloidal silver was adsorbed on activated carbon through electrostatic force and Van der Waals forces while both the Reactive blue X-BR and Alizarins were adsorbed on silver collide mainly through chemical absorptions. (c) 2006 Elsevier B.V. All rights reserved.