In this study, we investigated the effect of thymol on cognitive functions and the levels of glutathione (GSH), malondialdehyde (MDA), ApoE, reelin, LRP8, and Aβ1–42 in an AD model induced in male Wistar Albino rats via D-gal and aluminum chloride (AlCl3) application. The gene discussed is LRP8; the disease is Alzheimer disease.