The skin bacterium Propionibacterium acnes was incubated with PBV at various concentrations and bacterial growth was evaluated using the colony forming unit (CFU) assay. The mechanism of PBV employed in killing P. acnes was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, a total of 12 subjects were randomized in a double-blind, controlled trial to receive either cosmetics containing PBV or cosmetics without PBV for two weeks. Evaluations included lesion counts and skin microorganism