Agents and formulations and cells including plant extracts are useful in a method for controlling pathogen infestation in human and animal subjects. A method for inhibiting growth or infestation of a pathogen in or on a human or animal subject, includes contacting the pathogen with an effective amount of a combination of a plant defensin or a functional natural or synthetic derivative or variant thereof and either: (i) a proteinase inhibitor； or (ii) a chemical pathogenicidic or pathogenostatic agent； in a combined amount effective to inhibit growth or infestation of the pathogen.
