Western herbal medicine tends to use plants native to the British Isles, although Western medicine in Britain has a long and varied tradition.
Its roots lie both in Europe, with influences from Ancient Rome, and as far away as North Africa. More recently in the late nineteenth and early twentieth century, herbs used by the Native Americans made a transatlantic passage to become incorporated in the Western herbalists repertoire. Echinacea is a notable example of this inclusion.
A medical herbalist will choose herbal remedies according to a system of diagnosis not unlike that of orthodox Western medicine. Certain herbs are therefore associated with certain conditions.
Much of orthodox Western medicine has its roots in herbal medicine as many modern drugs have been derived from herbs.