A total of 28 traditional drinks derived from 23 plant species in 19 families were tested for their in vitro growth-inhibiting effects against Bifidobacterium adolescents, Bifidobacterium bifidum, Lactobacillus acidophilus, Lactobacillus casei, Clostridium perfringens, and Escherichia coil using a paper disc agar diffusion method under anaerobic condition. The responses varied with bacterial strain, plant species and tissue sampled. In a test with C. perfringens at 5 and 10 mg/disc, potent growth inhibition was produced from the extracts of Eucommia ulmoides stems, Pinus densiflora leaves and shoots, Thea sinensis leaves (green and oolong teas) and Zingiber officinale roots. All materials tested did not adversely affect the growth of bifidobacteria, lactobacilli, and E. coli. These results may be an indication of at least one of the pharmacological activities of these plant-derived drinks.