To test the hypothesis that berberine might inhibit the inflammation factors IL-1β and iNOS expression in the rat model of AD, we used the rat model of AD established by injecting Aβ(1–40)(5 μg) into the bilateral hippocampuses with stereotaxic coordinates and gave the rats berberine chloride (50 mg/kg) intragastricly for 14 days. The gene discussed is NOS2; the disease is Alzheimer disease.