As part of our search for less toxic antimicrobial substances from natural resources, naringin was isolated from feels of Citri fructus and then hydrolyzed to naringenin. The antimicrobial activity of naringenin was examined by measuring the minimal inhibitory concentration(MIC) against fourteen species of bacteria. The antimicrobial activity of narngenin in combination with rutin or hesperetin was evaluated by checkerboard method. Among fourteen species tested, the antimicrobial activity of naringenin was the most prominant against Staphylococcus aureus and Shigella boydii showing MIC of $100;{mu}g/ml$ for both species. Combinations of naringenin with rutin or hesperetin showed synergism against several species of bacteria, but no antagonism was observed.