My problem with most homeopathy/herbalism are many. Here aresome off the top of my head.
There is so little well done science that it is really hard to draw any conclusions at all. Often the research has no control group.
There is seldom any data on the side effects of the treatment.
There is no standardization of product. Method of processing can dramatically affect the chemical composition of an herbal product. Since we don't know what the active ingredient is, we can't know which processing method works best. (this is better in Germany where this is better regulated).
If the benefit is present in the fresh product, does it degrade over time
By the time most "natural" products reach the consumer it has been processed so much that it isn't natural anymore.
Many ingredients come from places where insecticides on crops for human consumption is poorly regulated. Same goes for sanitation.
So, basically you are at the mercy of the ethics of the producing company.
I would rather trust the FDA.