Abstract: The present invention relates to methods of dispersing biofilms comprising Gram-negative bacteria, the methods comprising exposing the biofilm to an epoxytiglienone compound or a salt thereof. Methods of treating infections comprising the localised administration, for example, topically or by injection, of an epoxytiglienone compound into or onto an established biofilm comprising Gram-negative bacteria to disrupt the structure of that biofilm and methods of preventing biofilms comprising Gram-negative bacteria forming or dispersing biofilms comprising Gram-negative biofilms that have formed on medical devices are also described.