Table 2 shows that the activities of glutathione peroxidase, superoxide dismutase, and catalase were reduced in the hippocampus and the supernatant of the cerebral cortex of the rats with AlCl3-induced AD (P<0.01), and that the MDA content increased in the supernatant of the hippocampus and cerebral cortex and the erythrocytes of the jugular blood of rats with AlCl3-induced AD. The gene discussed is CAT; the disease is Alzheimer disease.