The present invention relates to: a composition for inhibiting biofilms, containing, as an active ingredient, a peptide derived from human β-defensin-3； and a method for inhibiting biofilms by using the composition. The peptide according to the present invention inhibits bacterial biofilms even when used alone and exhibits a remarkably increased biofilm inhibitory effect when used in combination with a conventional dental therapeutic agent, and has an effect of preventing a tooth discoloration side effect caused by a conventional dental therapeutic agent.
