Abstract: A method for reducing dental plaque, pellicle and infections of the teeth, the present invention essentially comprises application of an effective amount of n-undecylenic acid or an effective substitute therefor according to the invention to the teeth, gums and mouth. The effective ingredient employed according to the method of the invention can either be applied directly to the teeth and tissues in a substantially inert carrier such as in a dentifrice paste for personal oral use or can be applied directly by a dental practitioner.