AIM:To elucidate molecular mechanism of chernopreventiveefficacies of garlic against human gastric cancer(HGC).MEthODS:HGC cell line BGC823 was treated with Allitridi(akind of garlic extract)and Allitridi-trested and parentalBGC823 cDNA libraries were constructed respectively byusing γZAP Ⅱ vector,cDNA Representational DifferenceAnalysis(cDNA RDA)was performed using BamH I cutting-site and abundant cDNA messages provided by the libraries.Northern blot analysis was applied to identify the obtaineddifference products.RESULTS:Two specific cDNA fragments were obtained andcharacterized to be derived from homo sapiens folatereceptorα(FRα)gane and calcyclin gene respectively.Northern blot results showed a 4-fold increase in FRαgeneexpression level and 9-fold increase in calcyclin mRNA levelin BGC823 cells after Allitridi treatment for 72 h.CONCLUSION: The method of cDNA ROA based on cDNA libraries combines the high specificity of cDNA RDA with abundant cDNA messages in cDNA library; this expands the application of cDNA library and increases the specificity of cDNA RDA. Up-regulation of FRa gene and calcyclin gene expressions induced by Allitridi provide valuable molecular evidence for the efficacy of garlic in treating HGC as well as other diseases. AIM: To elucidate molecular mechanism of chernopreventive efficacy of garlic against human gastric cancer (HGC) .MEthODS: HGC cell line BGC823 was treated with Allitridi (akind of garlic extract) and Allitridi-trested and parental BGC823 cDNA libraries were prepared respectively byusing γZAPII vector, cDNA Representational Difference Analysis (cDNA RDA) was performed using BamH I cutting-site and abundant cDNA messages provided by the libraries. Northern blot analysis was applied to identify the obtained resolution products. RESULTS: Two specific cDNA fragments were obtained and characterized to be derived from homo sapiens The folate receptor α (FRα) gane and calcyclin genes respectively. Northern blot results showed a 4-fold increase in FRαgene expression level and 9-fold increase in calcyclin mRNA level in BGC823 cells after Allitridi treatment for 72 h.CONCLUSION: The method of cDNA ROA based on cDNA libraries combines the high specificity of cDNA RDA with abundant cDNA messages in cDNA library; thi s expands the application of cDNA library and increases the specificity of cDNA RDA. Up-regulation of FRa gene and calcyclin gene expressions induced by Allitridi provide valuable molecular evidence for the efficacy of garlic in treating HGC as well as other diseases.