MedicineNet.com defines an antibiotic as: 'A drug used to treat infections caused by bacteria and other microorganisms. Originally an antibiotic was a substance produced by one microorganism that selectively inhibits the grown of another. Synthetic antibiotics usually chemically related to natural antibiotics, have since been produced that accomplish comparable tasks'.
Antibiotic resistance is a genetic trait, like brown hair or green eyes, but unlike these traits, antibiotic resistance transfers very quickly between one bacteria and another. Scientists are still trying to figure out how bacteria communicate with each other at extremely rapid rates.
Herbal antibiotics are different from pharmaceutical antibiotics. Many pharmaceutical antibiotics are isolated chemical constituents. They are one compound/one chemical -- penicillin is penicillin, tetracycline is tetracycline and so on. This makes it easier for bacteria to adapt & counteract. Herbs are much more complicated, for instance garlic has over 33 sulfur compounds, 17 amino acids and a dozen other compounds. Yarrow over 120 identified compounds. With plants, the whole appears to be more than the sum of its parts. Because of this, the different compounds work together, often to produce better than expected results.
Drug based antibiotics really should only be used for life threatening situations, or as a last resort...in my humble opinion. Even a short course of antibiotics can lead to resistant bacterial populations taking up residence in the gut that persist for up to 4 yrs. -- maybe even longer. Gut flora does not quickly return to normal after a round of antibiotics. So again, something to consider since over 75% of one's immune system is in your gut!
Some of the top antibiotic herbs I have found are: garlic, ginger, goldenseal, echinacea, clove, cinnamon, oregano, usnea, uva ursi & grapefruit seed extract. I am sure there are more, but in the different sources I checked out, these were the ones they all seem to agree upon.
Just remember too, you shouldn't take the antibiotic herbs indefinitely, the usual time is 7 days on, 2 days off. As with many herbs you don't have to wait 2-4 hours to do your next dose....