The purpose of this study was to investigate how thymol affects cognitive functions and the levels of MDA, GSH, Aβ1–42, ApoE, reelin, and LRP8 in an AD model induced in male Wistar albino rats with the application of D-galactose (D-gal) and aluminum chloride (AlCl3). The gene discussed is RELN; the disease is Alzheimer disease.