The present invention includes a composition for enhancing the antimicrobial efficacy of photodynamic disinfec-tion against Gram-negative organism that is receptive to paraben potentiation using a composition comprising a photosensitizer and at least one paraben. The present invention also includes a method for photodynamic disinfection comprising applying the composition to a desired treatment area and applying light to the desired treatment area at a wavelength absorbed by the photosen-sitizer so as to inhibit Gram-negative organism located within the treatment area wherein the Gram-negative organism is receptive to paraben potentiation.
