Abstract:The purpose of this study was to explore the relationship between the changes of immune indexes and the structure of intestinal microflora in fresh areca nut water extract（FANE）gavage mice.Serum cytokine interleukin 1（IL-1），alpha tumor necrosis factor（TNF-α），immunoglobulin A（IgA），IgG and IgM level of each group of mice were analyzed and weight gain were calculated.Besides，the abundance of colonic microflora was analyzed by high throughput sequencing.The results showed that low-dose FANE significantly increased the concentration of IL-1 and decreased the levels of IgA and IgG.The administration of high-dose FANE resulted in a significant decrease in TNF-α，serum IgA and IgG，and a significant increase in IL-1 concentration and IgM level.This indicated that high-dose FANE could induce immune dysfunction in mice.Alpha diver－sity analysis of mice intestinal flora showed that low-dose FANE group（A1）and the control group（F）had similar intestinal flora abundance and diversity.While the diversity of intestinal flora in the high-dose group（A2）was much lower than that in the other two groups.The ratio of Firmicutes/Bacteroidetes in the phylum level of A2 group increased significantly，which may be related to the change of energy utilization in food.The significant increase of Akkermansia，Enterorhabdus and Staphylococcus on the genus level may reflect the occurrence of intestinal inflammation and infection as well as Zn deficiency.In particular，chronic diarrhea in this group of mice might have contributed to these results.These analyses suggested that significant changes in gut microbial structure may play an important role in the changes in immune indices and function in mice.