Recently, it has been shown that triplet of methylene blue gets quenched by Au nanoparticles (J. Am. Chem. Soc. 132 (2010) 6298). Herein, we have shown that the reactivity of triplet crystal violet (CV), produced by ionizing radiation, is low towards Ag nanoparticles contrary to Au nanoparticles. Using absorption and surface-enhanced Raman spectroscopy (SERS) we have further examined the interaction of CV with Ag and Au nanoparticles. It has been shown that the polarizability of CV changes with the excitation wavelength and it is independent of metal nanoparticles. (C) 2013 Elsevier B.V. All rights reserved.