If you wait long enough, some fads come back around.
Take chaga fungus, for instance. It's one of those folk medicine remedies that have been used in Russia and other Northern European climes for centuries but that modern-day purveyors have to be careful to say "isn't intended to diagnose, treat or cure disease."
The thing is, chaga fungus grows on birch trees and will kill them. So harvesting it is good for the birches, at least.