Why is an antiseptic used to treat a cut?

Answer 1

Antibiotics are typically used to treat systemically, so are taken by mouth, injection, etc. Barring a severe infection, you wouldn't use antibiotics (by this name) for a minor cut. What you would use is an antiseptic, which is typically applied topically to wounds. That said, I generally prefer non-gooey antiseptics in most cases, because the sticky ones can trap bacteria. This leaves things like hydrogen peroxide 3% (which is strong -- sometimes too strong) and Betadyne (an iodine derivative). Neither hurt much on application, and they work really well. Alcohol is a bad idea -- in fact it's more of a disinfectant than an antiseptic (i.e. not used on open wounds). Gels like Bacitracin and their like are good if you need the gel to stick to the wound but -- as I mentioned before -- being sticky they'll trap things too. Wounds on mucous membranes seem to work well with gels because the normal flow of saliva will tend to wash away non-viscous liquids. ---- Topical antibiotics, such as neosporin, bacitracin, or triple antibiotic ointment (polymyxin, neosporin, and bacitracin) are typically prepared in a vaseline base and applied to a wound underneath a bandage. These promote healing by keeping the wound moist. They tend to decrease scar formation by promoting more rapid epithelialization of the wound base (if the laceration is small), and they help keep bacteria and other contaminants out.

That said, they can sometimes get messy, but if applied correctly and under a bandage, they can be quite effective.

Answer 2

To aid in prevention of infection.

(Anti- means against; -septic means infection)