– β-Defensin-3 is a peptide with antimicrobial properties that protects the skin and mucosal membranes of the respiratory, genitourinary, and gastrointestinal tracts. It inhibits the growth of the periodontopathogenic and cariogenic bacteria F. nucleatum, S. mutans, S. sobrinus, S. salivarius, and L. casei (MICs = 12.5-100 mg/l). It also inhibits the growth of S. aureus, S. pyogenes, P. aeruginosa, E. coli, and C. albicans. β-Defensin-3 stimulates gene expression and production of IL-6, IL-10, CXCL10, CCL2, MIP-3α, and RANTES by keratinocytes when used at a concentration of 30 μg/ml. It also stimulates calcium mobilization, migration, and proliferation of keratinocytes when used at concentrations of 30, 5, and 20 μg/ml, respectively. β-Defensin-3 induces IL-31 production by human peripheral blood-derived mast cells in vitro when used at a concentration of 10 μg/ml and by rat mast cells in vivo following a 500 ng intradermal dose.