Abstract: An aqueous composition adapted to kill bacteria in both planktonic and biofilm states is lethal toward a wide spectrum of gram positive and gram negative bacteria as well as other microbes. The composition, which is slightly to moderately acidic, includes a significant amount of one or more surfactants and large amounts of osmotically active solutes. The composition can be applied directly to a site of bacterial growth. Even when the bacteria is in biofilm form, the surfactant component(s) begin to kill the bacteria before the macro-molecular matrix is removed or dislodged from the site.