First rule of toxicology, EVERYTHING is toxic. That's sort of the big point of the naturalist fallacy with regards to medicine. Even water can kill you. It all comes down to molarity. Toxicity is what makes medicine, medicine. Everything listed in this thread works because it either degrades cellular membrane, dehydrates a cell to point of death, interferes with transfer of oxygen, or other such rather nasty mechanisms. If there were any point I wish I could make clear to all the homeopathists of the world, its this here. There is no such thing as a non-toxic compound. Safe, is merely a matter of relative concentration. Toxicity, is why "medicine" is more powerful than "folk remedy." The very thing that people complain about with medicine, is the reason why it works to begin with. No one competent, ever argued that medicine was "good" for you. Its simply less bad for you than the infection you are trying to kill. And there's a danger the other way. If you take something that is not strong enough to actually kill what you are trying to get rid of, you now select for even stronger resistance in what you failed to kill.
Down south its always funny when you look at what people traditionally eat. Pokeweed soup, anyone?