Turns out that quality control isn’t quite up to par when processing assorted plants and other natural substances for “medicinal” use. From the abstract:
RESULTS: Twenty-six systematic reviews met our inclusion criteria. Most commonly [herbal medicinal products] were adulterated or contaminated with dust, pollens, insects, rodents, parasites, microbes, fungi, mould, toxins, pesticides, toxic heavy metals and/or prescription drugs. [emphasis mine] The most severe adverse effects caused by these adulterations were agranulocytosis, meningitis, multi-organ failure, perinatal stroke, arsenic, lead or mercury poisoning, malignancies or carcinomas, hepatic encephalopathy, hepatorenal syndrome, nephrotoxicity, rhabdomyolysis, metabolic acidosis, renal or liver failure, cerebral edema, coma, intracerebral haemorrhage, and death.
So not only is this crap not proven to do anything at all, it’s often contaminated with actual crap. In fact, when it really does do something, chances are it’s because it contains actual drugs (see emphasis above). The difference is that drugs are manufactured under conditions that are, you know, regulated. That means that (hopefully) someone is coming around making sure the facility is clean enough so that you’re not getting bugs in your drugs.
Knowing this, the only that can be said for homeopathy is that at least you’re diluting the crap out of all of this crap (literally). Then again, if the water is contaminated, you’re really screwed.