Alzheimer’s disease irreversibly and progressively damages the brain, but the treatments in clinical trials are too slow. So, we hypothesized that the presence of erythrocyte variants with AD could be used as a noninvasive means to predict or trigger for administration of the preventive therapeutics, and the aim of this study is to develop a method using Raman spectroscopy in a rat model of Aβ25−35 -induced neurotoxicity, and then evaluate the protective effect of bajijiasu by this method. Results showed that the Raman spectra fingerprints of the erythrocyte of model group were obvious different from those of the normal control, as peaks around the region 650 cm−1 belonged to the s–s makers, 1605 cm−1 corresponded to the high spin (deoxygenated-Hb) marker, 1374 cm−1 arises from ν4 as a sign of concentration of O2 , and 1123 and 1033 cm−1 are associated with the trans stretching vibrations of CAC skeleton. Results also showed that bajijiasu can make these changes recover. Our study also suggested that erythrocyte variants detected using Raman spectroscopy should be tested in a specific longitudinal study for the association with AD diagnosis, and if positive, can be used as a prognostic marker.