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 and Ignaz Semmelweis.

Some common antiseptics are:

• Alcohol: Used to disinfect the skin before injections are given.
• Quaternary ammonium compounds (such as Benzalkonium chloride): Used as a pre-operative skin disinfectant. Antiseptic towels are often impregnated with this chemical.
• Boric acid: Uses in suppositories to treat yeast infections of the Censored page, in eyewashes, and as an antiviral to shorten the duration of cold sore attacks. Put into creams for burns.
• Chlorhexidine Gluconate: Used as a skin disinfectant and to treat inflammation of the gums (gingivitis)
• Hydrogen peroxide: Used as a 6% (20Vols) solution to clean and deodorise wounds and ulcers.
• Iodine: Usually used in an alcohol solution to disinfect minor wounds and as a pre- and post-operative disinfectant.
• Mercurochrome: Reportedly works better than any other antiseptic. Banned in USA by the FDA, ostensibly due to the mercury poisoning scare.
• Phenol compounds: Used as a "scrub" for pre-operative hand cleansing. Used in the form of a powder as an antiseptic baby powder, where it is dusted onto the belly button as it heals. Also used in mouthwashes and throat lozenges, where it has a painkilling effect as well as an antiseptic one.
• Sodium chloride: Used as a general cleanser. Also used as an antiseptic mouthwash.
• Ultraviolet light: Used for sterilization of laboratories, hospitals, and washrooms, as well as to sanitize drinking water.