Historical Use vs Clinical Evidence in Traditional Medicine

Historical use vs clinical evidence

A remedy that people have used for centuries has passed one test: it has been used. That is a good reason to study it, and it is not the same as showing that it works, in whom or compared with what, or how safe it is. Clinical evidence comes from comparing a treatment with something else, ideally in trials where people do not know which they received. Many traditional practices cannot be easily blinded, so expectation can shape results; this is true for conventional care too, which is why comparisons with placebo or usual care matter.

This site uses plain labels: established, promising but limited, mixed, insufficient evidence, no good evidence of benefit, evidence of harm, preclinical, traditional use only and marketing claim. The same standard applies whether the remedy is traditional or new.

When tradition pointed to something real

• Artemisinin. The Nobel Prize committee describes how, in the late 1960s, Tu Youyou turned to traditional herbal medicine to find new malaria treatments. A large screen of herbal remedies in infected animals pointed to an extract of Artemisia annua. Results were inconsistent, so she revisited the ancient literature, found clues that guided her extraction and showed that the purified compound was highly effective against the malaria parasite. [1] The tradition suggested a candidate; the laboratory and clinical work did the proving.
• A wider pattern. A review of plants used as drugs identified 122 compounds from 94 plant species and found that 80 percent had an ethnomedical use identical or related to the current use of the active compound. [2] That says traditional use can be a useful lead for researchers. It does not say any given traditional herb works.
• Pelargonium. A traditional southern African remedy became a commercial product with clinical studies; a Cochrane review rated the evidence for a liquid extract in bronchitis as low quality. [3][4] See Latin American and African herbal traditions.

When long use was not a safety guarantee

In Belgium, more than 100 patients developed a progressive kidney disease, often with urinary tract cancers, after taking slimming pills that contained the Chinese herb Aristolochia fangchi. The condition is now called aristolochic acid nephropathy. Cases have been seen worldwide, and the authors say the complexity of traditional pharmacopoeias, with frequent substitution of one botanical for another, raises the risk in some places. [5] The lesson is that a traditional name on a label does not tell you what is in the product, and that herbs can harm even when a tradition values them. Read product quality and contamination.

Regulators also separate the two ideas. The European Union registers traditional herbal medicines without clinical trials if they have been used for at least 30 years, including at least 15 in the EU, and sufficient safety data and plausible efficacy are shown. [6] A traditional registration therefore shows long use and an acceptable safety review. It does not show benefit.

Oral and written knowledge traditions

The World Health Organization defines traditional medicine as codified or non-codified systems for healthcare and well-being, originating in different historical and cultural contexts and pre-dating biomedicine. [7] The examples in this category show both kinds.

• Written and codified. Sowa Rigpa training is built around a twelfth-century written medical text, the Four Tantras. [8] Siddha literature was inscribed on palm-leaf manuscripts and stone, preserved by temples and other institutions. [9]
• Oral, local and restricted. Many communities pass knowledge person to person. Kallawaya healers' knowledge in Bolivia has been documented, but the book is kept exclusive to Kallawaya communities. [10]
• Why this matters for evidence. Written texts can be compared and dated, though not all claims in them are tested. Oral and community knowledge may be unavailable to outsiders, so a lack of public evidence is not the same as a lack of knowledge, and also not evidence of effect. Respect for knowledge holders is covered on the Indigenous and community traditions page.

Cultural context and translation

Translation changes meaning. The Tibetan term rlung is usually rendered as "wind," yet researchers explain it is a conflation of two Sanskrit concepts, vata and prana. [8] "Oriental medicine" lumps together Chinese, Korean and Japanese traditions that developed differently. [11] A Kampo review notes that it is risky to use Kampo or Chinese formulas outside the context of their own diagnostic paradigm. [12] And a trial designed around a Western diagnosis may not match how a practitioner of the tradition would treat the person. [13]

Plant identity is another trap: the kidney-disease example above involved one herb being substituted for another. [5] When reading a claim, ask for the exact plant (the Latin name), the part used and the preparation.

How to read a traditional claim

1. Which tradition, in which place and period?
2. Is the claim a traditional explanation, a lab finding or a human trial outcome?
3. If there is a trial: which product, how many people, compared with what, and for what outcome?
4. Has anyone checked what is in the product?

For more on safety claims see evaluating safety claims and the Research Library.

Related pages

See TCM traditional frameworks vs biomedical explanations and Ayurveda: traditional frameworks vs biomedical evidence.