It contains acetic acid, which can act as an antibacterial agent (sorry bacteria). However, unlike tea tree oil, it does not affect fungus.

Personally, I'd rather use vinegar to clean than bleach. Bleach is pretty nasty and caustic stuff, if you ask me. Regardless, I'm constantly reminding myself that the two should never be mixed together, same goes for ammonia and bleach. I always tell myself to never mix anything with bleach except water.

But anyway, back to vinegar. Wikipedia states that vinegar "is not effective against infections, lice, or fungus". However, in some quick research I've done, it seems like a lot of people believe it to be effective against fungus. This is worthy of further investigation!

Looks like Wikpedia was right, who would have thought! Medscape General Medicine published an article by Carol S. Johnston, PhD, RD and Cindy A. Gaas, BS titled "Vinegar: Medicinal Uses and Antiglycemic Effect". In the article, the authors clarify that "scientific investigations clearly demonstrate the antimicrobial properties of vinegar" were done in the context of food preparation, and that "Experts advise against using vinegar preparations for treating wounds."

Now that I've done a little research, I'll probably use vinegar as a general purpose cleaner. For tough disinfecting, I'll probably use isopropanol alcohol, and as a wound antiseptic, small amounts of tea tree oil. Sodium bicarbonate (baking soda) is also used by some as a disinfectant and antiseptic. Thankfully vinegar, baking soda, and isopropanol alcohol are all commonly available and inexpensive.

Thymol looks like an interesting antiseptic too. I say interesting because its all natural (usually extracted from thyme), but that doesn't necessarily mean its non-toxic. I couldn't find specific information about thymol's toxicity.

UPDATE: I found some at the EPA.gov website where they conclude that thymol is non-toxic. Unfortunately, its not the easiest publication to read, so I'll share this quote:

Thymol is an essential oil that is extracted from thyme and mandarine and tangerine oils and is FDA approved when used as a synthetic flavoring (21 CFR 172.515), a preservative, and indirect food additive of adhesives (21 CFR 175.105). Additionally, the source plant (thyme), from which thymol is extracted is acknowledged by FDA as generally recognized as safe (GRAS) (21 CFR 182.10, 21 CFR 182.20). Residues of thymol can be found in other food stuffs either naturally such as that found in lime honey or intentionally added to foods such as ice-cream, non-alcoholic beverages, candy, baked goods, and chewing gum. Based on the following, the Agency has concluded that thymol has minimal potential toxicity and poses minimal risk:

1. Thymol is a normal constituent of the human diet and a component of many non-pesticidal consumer products currently marketed in the United States,

2. Thymol and the phenols of thymol are listed as food additives by the FDA (21 CFR 172.515; synthetic flavoring substances and adjuvants),

3. Thymol is found naturally occurring in thyme herb, a food seasoning ingredient that is generally recognized as safe (GRAS) by the FDA (21 CFR 182.10),

4. Thyme oil (for which thymol is a component) also is recognized as a GRAS essential oil by the FDA (21 CFR 182.20),

5. Thymol can be presumed nonpersistent in the environment based on knowledge of its composition,

6. As a conventional pesticide, thymol repels vertebrate pests by a non-toxic mode of action,

7. The available toxicity information does not indicate toxic effects at the levels of potential exposure and

8. EPA is not aware of any adverse effects to humans or the environment in the scientific literature associated with any thymol related use.

Source: http://www.epa.gov/EPA-PEST/2006/January/Day-18/p436.htm