What’s in traditional Chinese herbal medicine, and do its prescriptions work?

If you've ever walked into an apothecary for traditional Chinese medicine (TCM), it's hard to ignore the tang of dried herbs that are arrayed on the floor, lining the counter, and stacked on floor-to-ceiling shelves. There's a good chance any brew you buy won't taste great either. Despite the smell and taste, many people around the world swear by TCM, using it to treat various ailments or as supplements to bolster general health. A large fraction of TCM ingredients come from plants, and the active compounds are their metabolites. Plants are amazing chemists—they can't run from danger or environmental stressors, so they have no choice but to synthesize their way to survival. Their strategies include secreting bitter or toxic compounds to deter consumers in the wild. Occasionally, some of these chemicals are potent enough to treat human health conditions. For as long as humans have been hunter-gatherers, our ancestors have