This paper reports a new application of surface enhanced Raman scattering (SERS) in analysis of oxidation of glutathione (GSH) to oxidized glutathione (GSSG), an important biochemical redox reaction in biological systems, under oxidative stress imposed by dielectric barrier discharge (DBD). Using the silver nanoparticles (NPs) prepared through the reduction of AgNO₃ by beta-cyclodextrin (β-CD), the transformation of GSH to GSSG under DBD irradiation can be probed with only a small quantity of sample at low concentration. Based on the intensity ratio of two characteristic Raman bands, i.e., the band at 1051 cm⁻¹ (C–N stretching) and the band at 509 cm⁻¹ (S–S stretching), which stem respectively from GSH and GSSG, the conversion between the reduced and oxidized glutathione can be determined quantitatively. This work demonstrates another useful extension of the SERS technique applied to bioscience research, i.e., rapid probing and quantitative assessing of chemical reactions of biomolecules under oxidative stress conditions.