Objective： To study the effect of Tiantai No. 1 （天泰1号） on gene expression profile in hippocampus of Alzheimer＇s disease （AD） rat, molecular genetic target points of the effect of this drug were defined, its molecular genetic pharmacodynamic mechanism of anti-AD was further explored at molecular gene level, and a scientific basis was provided for its clinical availability and promotion. Methods： Thirty male Sprague- Dawley rats were divided into three groups with 10 rats per group： sham-operation group, model group and Tiantai No. 1 group. Sterile surgical procedure was applied, the model group with bilateral hippocampal injection of Aβ21-40 was established, and normal saline was used instead of Aβ1-40 in the sham-operation group. One week after the models was made, rats were administered by gastric lavage once every day for three consecutive weeks. The rats of the sham-operation group and the model group were daily fed with purified water by lavage; the rats of the Tiantai No.1 group treated group were administered with Tiantai No.1 by lavage. Total RNAs of hippocampus tissues were extracted with Trizol, the changes of hippocampus gene expression profiles in the above throe groups were analyzed by using Affymetrix rat whole genome expression profile microarray. Results： Microarray analysis showed that, compared with the sham-operation group, the hippocampus of the model group had 50 up-regulated genes with significant difference （fold change 〉2）, and 21 down-rogulated genes with significant difference （fold change 〈0.5）; compared with the hippocampus of the model group, the hippocampus of the Tiantai No. 1 group was found to have 5 up-regulated genes with significant difference （fold change 〉2） and 20 down-regulated genes with significant difference （fold change 〈0.5）. The functions of differonUally expressed genes of the groups were involved in nervous system＇s development, neuronic differentiation and function-regulation, cellular growth and differentiation an
