In this study, mixed plant extracts including Phellodendro namurense and Eucommia ulmides Oliv were tested for antimicrobial activity and safety. Antimicrobial activity was measured by disc diffusion method using normal skin flora and opportunistic microbes such as Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. As safety test, single dose oral toxicity test, single dose inhalation toxicity test and repeat dose inhalation toxicity test were done. From antimicrobial test, plant extracts showed significant antimicrobial activity Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, however, did not indicate any antibacterial effect on Escherichia coli. From 3 kinds of safety tests, toxicity of mixed plant extracts was not observed. From experimental results, mixed plant extracts including Phellodendro namurense and Eucommia ulmides Oliv showed good potential for natural antimicrobial agent.