Abstract: This study aimed to investigate the effects of Lactobacillus helveticus on intestinal microflora in mice and analyze the variations regularity of microflora after mice were administered with probiotics by gavage. Mice were randomly divided into four groups: normal group, normal saline as control, Lactobacillus helveticus group, and E.coli group. They were administered for 15 days (The normal group mice were fed like before). During the 15 days, the numbers of bacteria in the intestine of mice were counted. The numbers of Lactobacillus, Btfidobacterrim, Enterobacteria and E.coli in Lactobacillus helveticus group show extremely significant dfference to those in normal group and normal saline as control (p<0.01), and the number of Enterococcus shows significant difference (p<0.05). Compared with control group, there is also significant difference (p<0.05) on the numbers of the other bacteria except Enterococcus in E.coli group. Lactobacillus helveticus can increase the number of probiotics and that of decrease harmful bacteria, so it can regulate the intestinal microflora in mice.

Key words: Lactobacillus helveticus, Escherichia coli, intestinal microflora