If there's one thing I've been consistent about, it's that, however ridiculous all the other woo I routinely discuss here is—homeopathy, reiki, reflexology, I'm talking to you and your friends—herbal medicine and supplements might have value because they might have a physiological effect that is beneficial in treating or preventing disease. Of course, if that's the case, it's because the herb or supplement contains chemicals that act as drugs. They're "dirty" drugs in that they are mixed with all sorts of other substances in the herb or supplement that might or might not have effects, which…