This study was carried out to evaluate the effect of bacteriocin produced by Lactococcus sp.HY 449 against skin-inflammatory bacteria such as Staphylococcus epidermidis ATCC 12228, Staphylococcus aureus ATCC 65389, Streptococcus pyogenes ATCC 21059, and Propionibacterium acnes ATCC 6919. The spot-on-the-lawn method was used to determine the antimicrobial activity of bacteriocin against indicator strains on the human skin. The bacteriocin produced by Lactococcus sp. HY 449 inhibited the growth of S. epidermidis ATCC 12228, S. aureus ATCC 65389, Strep. pyogenes ATCC 21059, and P. acnes ATCC 6919. The treatment of crude bacteriocin caused a rapid inactivation of P. acnes ATCC 6919. The LC(50) of bacteriocin on human fibroblast was approximately 50mg/ml at which the inhibition of cell proliferation was not observed. Neither any irritations nor allergic reactions by the bacteriocin were evident in a human patch test. The bacteriocin produced by Lactococcus sp. HY 449 may be a useful antimicrobial substance to control the growth of P. acnes and to prevent skin-inflammation and acne.