Hexenolactone exerted an antibacterial action against a variety of gram-positive and gram-negative bacteria. Hexenolactone was bactericidal in concentrations of 1:100 to 1:400; bacteriostatic in concentrations of 1:200 to 1:1000; inhibitory in concentrations of 1:1000 to over 1:3200; depending on the test organism. In some instances, increased concentrations of hexenolactone resulted in decreased antibacterial activity.