Puerarin and daidzin have been isolated from Puerariae thunbergiana Benth. Structures were determined by spectroscopic methods. Compounds showed weak antimicrobial activity against S. mutans, S. epidermidis, S. aureus, and C. albicans (MIC, $800{mu}g/ml$). However, these compounds were not antioxidative. Puerariae thunbergiana Benth. extracts against microorganisms were evaluated in terms of the minimum inhibitory concentrations (MIC). In general, C. albicans was stronger antimicrobial activity than the other microorganisms. The antioxidative activity of was observed in the etyl acetate extract ($IC_{50},;119.87{pm}0.16;{mu}g/ml$). The DPPH radical scavenging effect ($IC_{50},;1,673.3{pm}0.54;{mu}M$) of the puerarin was comparable with that of synthetic antioxidant, BHA $(IC_{50},;88.39{pm}1.1){ imes}10^{3}{mu}M$. These results suggest that puerarin and daidzin have a potential antimicrobial activity.