"The thing about herbs is that there is nothing supernatural or implausible about the fact that any particular herb can have a medicinal effect. But the truth of the matter is that herbs are drugs. There's nothing magical about them. The fact that they are "natural" is irrelevant — it's meaningless. They are drugs. They are drugs that have not been purified, identified, … and quantified. … Probably for most plants … there are hundreds of chemicals in there with varying degrees of potency."