Traditional herbalism

What it is

The medicinal use of plants within a transmitted body of practice — which is not one tradition but many, with different theories, different plants and different standards of evidence.

The major living systems are Western folk and professional herbalism; Traditional Chinese Medicine, where herbs are prescribed in formulas rather than singly and organised by a theory of pattern and constitution; Ayurveda, organised around the three doṣas; and a very large number of regional and Indigenous traditions with their own materia medica.

This page is about the practice as a whole. It is not instruction, and there are no doses on it.

Where it came from

It is probably the oldest continuous medical practice there is, and the documentary record is deep.

Dioscorides, a Greek physician serving with the Roman army, compiled De Materia Medica around 65 CE — roughly six hundred plants with descriptions and uses. It remained the standard European reference for over 1,500 years, which is a longer run than any medical text since.

The Chinese Shennong Bencao Jing was compiled in the early centuries CE and attributed to a mythical emperor; the Ayurvedic Charaka Samhita and Sushruta Samhita are of comparable antiquity. Islamic physicians — Avicenna above all — synthesised Greek and Indian material and transmitted it back to Europe. In England the tradition reached its widest audience through Culpeper, who printed it in English so ordinary people could use it without paying a physician.

How it is practised

Preparations are typically infusions, decoctions, tinctures, poultices or powders. Most traditions prescribe by constitution and pattern rather than by symptom alone, and most combine plants deliberately — TCM formulas are built around a principal herb with others intended to support it or reduce its harshness.

What we can and cannot say

We can say — clearly, because this site does not do reflexive dismissal — that plants work. A substantial share of modern drugs derive directly from traditional plant use:

• Aspirin from willow bark salicin
• Digoxin from foxglove, identified by William Withering in 1785 from a folk dropsy remedy
• Morphine from the opium poppy
• Quinine from cinchona bark
• Artemisinin from sweet wormwood, extracted by Tu Youyou from a fourth-century Chinese text and awarded the Nobel Prize in Medicine in 2015 — the clearest modern case of a traditional source yielding a genuinely important drug
• Paclitaxel from Pacific yew

Anyone who says herbal medicine is nonsense has to explain that list.

And the same fact is the danger. Plants that are pharmacologically active are, by definition, capable of harming you. The specific risks are well documented:

• Interactions. St John's Wort induces liver enzymes and reduces the effectiveness of hormonal contraceptives, several antidepressants, anticoagulants, antiretrovirals and immunosuppressants. Grapefruit works the other way, raising blood levels of some drugs to dangerous concentrations.
• Direct toxicity. Aristolochia causes kidney failure and urothelial cancer. Comfrey and several other plants contain hepatotoxic pyrrolizidine alkaloids.
• Dose variability. The active content of a plant varies with species, growing conditions, harvest time and preparation. A standardised tablet has a known quantity; a home preparation does not.
• Adulteration and contamination. Studies of imported traditional preparations have repeatedly found undeclared pharmaceuticals and heavy metals — research led by Robert Saper and colleagues, published in JAMA in 2004 and 2008, found detectable lead, mercury or arsenic in roughly a fifth of Ayurvedic products sampled from Boston-area shops, and a similar proportion of internet-purchased products.
• Misidentification. The Belgian kidney-failure cases arose because one plant was substituted for another in a supply chain nobody was checking.

We can say regulation is uneven. In Australia, therapeutic goods are regulated by the TGA and listed products must use permitted ingredients, but listed medicines are not assessed for efficacy before sale, and imported products bought online sit outside that system entirely.

We cannot give guidance here, and will not. The two things that are safe to say, and that belong on every page of this kind: tell your pharmacist or doctor everything you are taking, including anything herbal — they can check interactions in minutes and will not lecture you. And treat any practitioner who suggests stopping or delaying prescribed treatment as having told you something important about themselves.

Further reading

• Dioscorides, De Materia Medica — available in translation, and remarkable as an object.
• Tu Youyou's Nobel lecture (2015) — a first-hand account of extracting a real drug from a traditional text, including everything that had to be done to make it work.
• The TGA (Australia) or your national regulator, for what is actually assessed and what is not.