A thin film composition for oral administration that adheres to and dissolves in a mouth of a user, wherein the thin film is a single layered water-soluble solid comprising at least one D-amino acid contained in a plurality of hydrophobic carriers dispersed throughout the thin film. The hydrophobic carriers comprise oil and the composition further comprises a phospholipid, an emulsifier, and a water soluble polymer. The preferred D-amino acids are D-leucine, D-tryptophan, D-methionine, and D-tyrosine. A method of reducing dental plaque in a subject entails placing the thin film composition contemplated herein into a mouth of the subject.