PROBLEM TO BE SOLVED: To provide an antimicrobial agent which exhibits excellent antimicrobial property even when directly or indirectly brought into contact with multiple kinds of anaerobic bacteria in oral cavity, especially to periodontosis offending bacteria, in a real oral cavity, which has good flavor, and which is suitable for continuous daily use a composition for oral cavity using the antimicrobial agent and food and drink.SOLUTION: The antimicrobial agent includes one or more kinds of fatty acid esters. Both of the composition for oral cavity and food and drink are prepared by using the agent. The fatty acid esters are selected from isoamyl acetate, isobutyl acetate, geranyl acetate, linalyl acetate, ethyl acetate, propyl acetate, octyl acetate, citronellyl acetate, nerol acetate, bornyl acetate, isobornyl acetate, terpinyl acetate, myrcenyl acetate, benzyl acetate, phenylethyl acetate, cinnamyl acetate, anisyl acetate, and acetylisoeugenol.
