More than 5000 years ago the humans began using plants as shrubs and herbs for spicery or medicine. The old first writings from Egypt and China describes herbs, like the Turkey rhubarb, which up to now has reputation of being medical significant. During all those millenniums the herbalism methods has had great cultural climaxes but also its down hill devaluations. In the Middle Ages the herbs were particularly attended with black magic and witchery.
A notorious example of such false teaching is the so-called signature doctrine from the famous nature philosopher and doctor Paracelsus (1493-1541), which teached that "equal cures equal" which as an example means if a plant had kidney formed leaves it was a sure sign of its capacity of curing kidney diseases - or walnuts, because of their brain shaped shells had powers to cure head aches, etc. This doctrine has shown persistent existence and may even be heard today.
The herbalism is not at the end of a long historic event, but on the contrary inaugurating a new promising era. This is been possible because of new technical laboratory skills as chromatography, photometry, etc., and above all, an increased health consciousness by the public.