An antiseptic is a substance that kills, or prevents the growth of, bacteria on the external surfaces of the body. It can be contrasted with antibiotics which perform a similar function within the body, and disinfectants which operate on nonliving objects such as medical instruments.

The widespread introduction of antiseptic surgical methods followed the publishing of the paper Antiseptic Principle of the Practice of Surgery in 1867 by Joseph Lister, inspired by the findings of Louis Pasteur. Some of this work was preceded slightly by that of Dr. George H Tichenor.

Some common antiseptics are alcohol, iodine, hydrogen peroxide and boric acid..