As adjectives the difference between antiseptic and antimicrobial is that antiseptic is of, or relating to antisepsis, or the use of antiseptics while antimicrobial is tending to destroy or capable of destroying microbes. As nouns the difference between antiseptic and antimicrobial is that antiseptic is any substance that inhibits the growth and reproduction of microorganisms generally includes only those that are used on living objects (as opposed to disinfectants”) and aren’t transported by the lymphatic system to destroy bacteria in the body (as opposed to ”antibiotics ) while antimicrobial is an agent that destroys microbes, inhibits their growth, or prevents or counteracts their pathogenic action.