化妝品中合成抗菌劑（如Methyl Paraben(M.P.)、Propyl Paraben(P.P.)）的過度 使用，經常造成皮膚過敏。因此，尋找替代以及減少合成抗菌劑成為化妝品業界 的重大課題。本研究以抑制大腸桿菌為指標，檢討中草藥廣藿香萃取物與化妝品 中常使用的杏仁酸及合成抗菌劑之間的體外交互（協同、加成、拮抗）作用。實 驗結果顯示，中草藥廣藿香分別與杏仁酸、M.P.及P.P.一起結合使用時，對於抗大 腸桿菌的能力均具有良好的協同或加成作用。這意味著，化妝品中合成抗菌劑M.P. 和P.P.的配方用量可加以減少，增加以天然成分的廣藿香和杏仁酸用量進行取代， 而仍能維持化妝品的整體抗菌能力。

Artificial antibacterial agents (such as Methyl Paraben(M.P.) and Propyl Paraben(P.P.)) were key factors in causing skin allergies. Therefore, searching for alternatives and decreases of the artificial antibacterial agents have become a major issue in cosmetics industry. This study evaluates the in-vitro interactions (synergism, addition effect, antagonism ) between methanol extracts of Pogostemon cablin, Almond acid and two kinds of common ingredients used in cosmetics, against Escherichia coli. The results of this study showed that Pogostemon cablin possessed good synergism or addition effects when it was combined respectively with Almond acid, M.P. and P.P.. This means that the formula amounts of M.P. and P.P. can be reduced and substituted by the increased using of Pogostemon cablin extracts and Almond acid in cosmetics, and the overall antibacterial ability of cosmetics could still be able to maintain.