To take the word natural first, as likely an act as most to ensure our survival would be to eat a leaf from a tree, bush or herbaceous plant, given that the plant cannot run away as can a prey animal. It might, though, put up physical defences such as thorns or chemical defences, given the prodigious capacity of plants to synthesise metabolites that will harm us and other aggressors. Medicine in this natural setting could be seen as turning these very metabolites to our advantage.
We will make Medicine, this second word of the title, even more complicated if we conflate a number of process’ with a number of products. We speak of the roots of medicine (plants provide not only the means for life but the most abundant metaphors) where we might more properly speak of its branches. Medicine is an inevitable outcome of the behavioural emotion inherent not only in humans but in all social primates. We may call it empathy or sympathy. Such responses constitute not only a universal norm, but its absence is considered unnatural as much as abnormal.
The empathic response to a person in some sort of trouble immediately involves emotional support by speech, gesture and tact as a gateway to, if the circumstances demand, technical support. This may be primary physical help, first aid or primitive surgery or seeking help elsewhere. As an adjunct or as a resolving agent, substances and objects may be offered to the hurt person, from a glass of water to a range of what might be thought medicinal. If a leaf is handy, and one usually is, even in a busy city thoroughfare, it would be natural to make use of it, if the knowledge or perception is in place.
The narrators of such an interaction with their attendant narratives change over time and the event becomes embedded in memory. The purview of Medicine arises from these interdependent acts, which may become specialised or even professionalised according to the hurt incurred and the circumstances. Medication (casually used as a synecdoche for Medicine) is a subsidiary part of the whole, a tendency that those who medicate have an interest in retaining. As a herbalist and natural pedant, I discriminate between herbal medicine and herbal medication. The purpose of such nicety is to do away with the medication standing in for the whole process and so may eliminate the absurdities involved in matching conditions, exactly abstracted, with their so–called remedies.
Medicine is one of the basic social enterprises which engages the emotional, technical and biological aspects of human beings. The type of medical intervention should depend upon each situation and call for the most appropriate response: when survival is threatened, urgent attention to technical and biological support is paramount; the emotional support can come later or from a different quarter. Apart from this temporary consideration, it is hardly natural to separate any of these three.
As medicine, in its widest sense, is always a human affair and, as we are part of nature, medicine is always natural. Technology and the technical mind have increased the range and availability of nutrients, at least to the lucky few at first, and now unluckily for the rest of nature, to the many. Technologies have allowed us to escape the ravages of the weather and have thus separated us from the more unremitting pressures of nature, and permit us to consider ourselves as to some extent outside its constraints. I would suggest that when people invoke the term ‘Natural Medicine’, they have in mind a form of medication or medicinal approach that arose before we acquired or entertained such a sense of separation. The separation or at least a sense of it has been gradual over millennia and has occurred at different rates and times for different people. We may table technological shifts, from the invention of the heavy plough perhaps 9000 years ago in Western Asia to the industrial revolution in Europe just a couple of centuries ago and the digital era on which we are newly embarked. The notion of a ‘Golden Age’, when life was simpler, nobler and more in tune with nature, is ubiquitous in both literate and pre–literate cultures and is shared by many religious and cultural traditions. I suspect that our sense of ‘Natural Medicine’ is not far from this ubiquitous nostalgia for a Golden Age. If this is true, a kind of moral superiority is inherent in its use along with an equivalent disparagement of medicine that is highly dependent upon technological intervention or medications that are industrially produced. As a confirmed and pedantic pluralist, I think such a separation is unrealistic and invidious, if not a strange hypocrisy for those of us who lead a life that is fully industrialised and protected. Even as we deplore the threats from modern life and try to escape its ravages by returning (‘back to nature’), we have a mind that enforces this unnecessary separation from the very separation so decried. Yet separation from the physical world is an absolute requirement of biological Life in equal measure as our necessary attachment to this physical substrate. It therefore makes no sense to describe the natural world as hostile or as friendly: it is paradoxically both at the same time and this paradox is fundamental to the survival of all living things and the physical planet would have a very different future (and possibly a shorter one) without living beings. Humans have always known this paradox very well and did not need modern science for it to be understood. What the scientific revolution brought about was a deeper knowledge of physics and chemistry, a realisation that the immutable Laws that govern the behaviour of matter can be mathematised. While life is a special case where its inner environment temporarily suspends these laws by dint of the extraction from the outer environment of a constant and consistent flow of energy, the laws are not broken, just deferred. They are delayed by establishing this inner space very far from equilibrium with the external environment. The point at which chemical equilibrium is reached, when the separation between these two spaces can no longer be maintained, is the point that marks the death of the organism. Separation from the physical world is inherent in biological forms, whether an amoeba, a carrot or a human. Our latter example, by elaborated technologies has built secondary buffers between itself and the physical world. Although there exists a deep nostalgia for the pre–technological age that none of us live in, it is expressed by a range of outdoor pursuits from camping and sailing to climbing mountains and trudging to the North pole. Perhaps the nostalgia is deeper in societies that rarely are forced to experience extreme discomfort. If that is the case, then you might expect to find a greater interest in Natural Medicine in more affluent communities.
To move from a rhetorical position to a historical perspective and ignoring the largely theocratic domain of medicine in pre–literate societies, we may discern in the Humoral theories of the Pre–Socratic Ionians a shift to an interest in natural phenomena as the key to knowledge about reality and the source of the quotidian miracle. Even before the biological observations of Aristotle, the Hippocratic tradition exhibits an ecological bias and an enquiry that we would now call epidemiological. These interests put observation before belief. They interpret shifts within the human microcosm as a reflection of movements in the material macrocosm. Such humoral theories analysed matter, form and forces then made a synthesis of these principles with respect to nature and the place of humankind in such a scheme. All such classifications have the binding power of social construction and consolidate the political order, whether that be Confucian, Ayurvedic, Hellenistic or Mayan  . As an analogic structure, humoral theory sought, and conveniently found, homologies within the part of the world that gives us food and sustains all animal life, and so gave us what we already possess, and called it herbal medicine. In so doing they might have distanced us all from the natural habit of eating leaves. In the later Hellenistic period, the Classical tradition of herbal medicine was catalogued by a handful of physicians such as Diocles, Crateuas and Dioscorides. Although the last of these is the most lauded by our contemporary herbalists, the physician who distilled learning from primary Greek sources was Cornelius Celsus. His compendium of medicine may be less encyclopaedic than Pliny (whom he preceded) but, by contrast, without the credulity.
Nature is messy. As humans become more urbanised they become more fastidious. They tend also to prefer convenient simplifications. These trends reinforce the social order and seek to exclude rustic empiricism. Over time, however, as the socioeconomic order becomes corrupt and messy (not in any way like the muddiness of nature), the practice of medicine becomes arbitrarily complicated in its reliance on dogma rather than observation. Medicinal mixtures became obscurantist and pointlessly complex in Europe  as the Plague conspired against the advances of the twelfth and thirteenth centuries. The religious hierarchy that permitted such degradation of ancient learning and medical practice was exposed to a reforming spirit as potent as the plague. Medicine itself seems to have been less besieged or more resistant to Reformation.
Reforming zeal is always attended by megalomaniac zealots with their lust for a purifying power to sweep away the murky accretions of a despised past. Reform, when it takes the form of rage unleashes a manic drive for simplicity which must eventually and inevitably lead to simplification. Metallurgy and Alchemy (as Chemistry was known in the late middle ages) seemed to Theophrastus von Hohenheim (1493–1541) to bring a simplifying, almost surgical precision to the diagnosis and treatment of disease. Although named after the ‘Father of Botany’, this Swiss Theophrastus did nothing to advance botanical science. Indeed, he performed a disservice to this realm of the natural world by popularising the entirely fortuitous Doctrine of Signatures. In his search for purity and essence, he previews modern medicine with its classification of illness as entity rather than process and the matching of symptomatology with such a construct. With precise posology and dosage, he prefigured both allopathic and homeopathic medicine. Not only was he unable to contain his rage against the medical establishment of his day, his megalomania caused him to adopt the name Paracelsus: superior—that is—to Celsus, the great Roman antecedent of the titanic Galen, whom he declared also to be his inferior. Thank goodness he did not wield political power! His attempt at revolution must, of course, be placed in the context of the transforming upheavals of his day. The binary between austere truthfulness and corrupt and venal abundance played out in European history between the Protestant reformation and the Catholic Counter–Reformation  . I have drawn attention to such binaries elsewhere  .
Ideas never die but they may wither on the bough of history. Contemporary orthodox medicine is conducting an attempt at reformation of its own under the banner of Evidence Based Medicine and matches that of the political process. It is an ingenious device which supports vested interests and the status quo while purporting to do the precise opposite; but it is the nature of revolutions to replace one tyranny with another. In the ragbag of medical history, encrusted with the remnants of ideas whose source is barely remembered except by scholars, the notion of the natural allied with the healing profession is at best a confused one. In its simplest manifestation, it might suggest that natural medication is from a material that is found in the natural world and which has not been industrially produced or modified. Very few medicines quite fulfil these criteria. Dietary and medicinal commodities are mostly the product of horticulture and agriculture, both of which are industries that have evolved along with the other commodities of the industrial revolution. Many herbal medicines are cultigens or their origins are lost in the course of their co–evolution with us since the time that the agricultural revolution sought to modify the constraints of Nature. It is still natural, however, (and perhaps uniquely so) to eat a leaf from a plant and it may be no less so than to encourage others to do the same for therapeutic purposes.
This unique character allows us to re–enact the prehistoric experience of the sensorium of humankind before the advent of agriculture and writing. The smell of the plant invokes the olfactory sense and connects, with very little synaptic interruption, to the limbic system itself. The taste of the plant provokes an arousal of the digestive tract with its adnexial organs. Taste and smell and the visual sense are integrated in the hypothalamus with the endocrine system and its procreative drives. All of this activity and patterning happens before any substance from the leaf enters the bloodstream in appreciable quantities. Priming precedes pharmacology. None of this is simple or pure, to the fury of purists. The signal is recognisable and distinctly variable. This similarity within variance is the hallmark of nature. A signal associated with noise; it is the noise that enhances the signal by the process known in electronic engineering as stochastic resonance, a subject that exceeds the space of this article  .
 Cf. Durkheim E & Mauss M Primitive Classification (trans 1963)
 E.g. theriacs Cf. Griggs B Green Pharmacy (1981, 1991, 1997)
 I am told by political observers that to make the parallel comparison between contemporary conflicts ostensibly between Shia and Sunni branches of Islam is to oversimplify in a Eurocentric attempt to make correspondences where they do not exist.
 in my History, Philosophy & Medicine ~ Phytotherapy in Context Winter Press 2006 2nd Edn revised 2014
 I have touched on this elsewhere, for instance in Herbal Exchanges NIMH 2014