Corni Fructus extracts were investigated for antimicrobial and antioxidative activities. In the methanol, ethanol, water extracts from Corni Fructus, antimicrobial activity of the water extract was stronger than the others. Antimicrobial activities were strong against microorganisms such as Streptococcus mutans, Bacillus subtilis, Pseudomonas aeruginosa, Salmonella typhimurium, Escherichia coli and Escherichia coli O-157, the activity against Escherichia coli O-157 was the strongest of all the microorganisms. The growth of all the microorganisms were completely inhibited to 48 hours in the 150${mu}ell$ per $mell$ of culture media. the shape of E. coli O-157 treated with Corni Fructus water extract was expended and its cellular surface was collapsed severely. When Corni Fructus water extract of 200${mu}ell$ was treated, hydrogen donating effect was more than 90%, and antioxidative activity using linoleic acid was similar to 0.1% BHT at the concentration of 50${mu}ell$.