To investigate the effect of wormwood extract on intestinal Microorganisms of human, we examined the changes of the intestinal microflora of 6 volunteers for 13 days. Numbers of total anaerobes in feces of 6 volunteers showed 1010cfu/g before and after intake of wormwood extract. In case of beneficial Microorganisms, wormwood extract did not have an effect on the growth of bifidobacteria and Lactobacillus spp. On the other hand, the growth of C. perfringens and E. coli, the harmful Microorganisms of human intestines, was inhibited by the wormwood extract.