There are roughly half a million species of plant in the World, and of these around 5 % have been studied in the laboratory. Of this small number less than 1000 medicinally useful substances have been identified and isolated. Healing plants have been known to civilizations for all of recorded history and likely much before that. Herbalism has roots in ancient populations who observed the use of such plants by animals, experimented themselves, or accidentally stumbled across medicinal uses. The shape and colour of the plants as well as the growing conditions, have been suggested as a guide to the medicinal use of the plant. While this viewpoint is controversial, what is less controversial is the ability of many herbs to provide medicinally useful substances in a safe and efficacious manner to humans and other animals. In fact many of the medicinally useful substances in plants cannot be synthesised in the laboratory and so much still be derived from plants.
Nearly all drugs available from modern medicine originate from plants or other living organism. It is only recently however that pharmacology has tried to isolate the healing substances from plants and concentrate them into pills. Prior to the development of modern allopathic medicine, it was traditionally the whole herb that was used for medicinal reasons. Isolating the active chemicals from plants at first glance seems to be advantageous because it provides a single substance that can be used at a precise dosage, and thus we are sold the myth of modern pharmacology. However, nature in its wisdom has created plants to contain cofactors and accessory components that balance the effects of the usually multiple active ingredients. In this way the whole plant is not only more effective that the synthetic isolated drug alternative, but also safer. The herb St John’s wort for example has been shown to be as effective as any modern pharmaceutical against mild depression, yet the side effects of the herb are significantly less (or absent) in comparison studies.