Abstract: The present invention relates to novel use of bacteriocin derived from Enterococcus faecalis SL-5. More particularly, the present invention relates to a composition for preventing and treating acne comprising a polypeptide of SEQ ID NO: 1 or SEQ ID NO: 2, which is a bacteriocin derived from Enterococcus faecalis SL-5. Also, it relates to use of the bacteriocin for the manufacture of an agent for preventing or treating acne, and a method for preventing or treating acne comprising administering or applying the bacteriocin to subject in need thereof. The present invention provides a polypeptide of SEQ ID NO: 1 or SEQ ID NO: 2 derived from Enterococcus faecalis SL-5, which shows excellent antibacterial activity against Propionibacterium acnes inducing acne. The inventive polypeptide can inhibit growth of Propionibacterium acnes by having excellent antibacterial activity against them inducing acne. Accordingly, the inventive polypeptide can be effectively used in preventing, treating and improving acne.