Gua sha: who cares how it works, when it is unproven that it works?

Gua sha, sometimes referred to as “scraping”, “spooning” or “coining”, is a traditional Chinese treatment that has also been adopted in several other Asian countries. It has long been popular in Vietnam and is now also becoming
well-known in the West. The treatment consists of scraping the skin with a smooth edge placed against the pre-oiled skin surface, pressed down firmly, and then moved downwards along muscles or meridians, the assumed ‘energy’ channels of traditional Chinese medicine. According to its proponents, gua sha stimulates the flow of the vital energy ‘chi’ and releases unhealthy bodily matter from blood stasis within sored, tired, stiff or injured areas.

An international team of authors has revisited gua sha, a therapy that we have discussed repeatedly on this blog (see here and here). The authors offer the following summary:

Gua sha is a traditional healing technique that aims to create petechiae on the skin for a believed therapeutic benefit. Natural healings are mostly based on repeated observations and anecdotal information. Hypothetical model for healing does not always fit the modern understanding. Yet, the mechanisms underlying Gua Sha have not been empirically established. Contemporary scientific research can now explain some events of traditional therapies that were once a mystery. It is assumed that Gua Sha therapy can serve as a mechanical signal to enhance the immune surveillance function of the skin during the natural resolving of the petechiae, through which scraping may result in therapeutic benefits. The current review, without judging the past hypothetical model, attempts to interpret the experience of the ancient healings in terms of contemporary views and concepts.

The authors conclude that this narrative review draws up a survey of scientific sources on an ancient healing, scraping therapy. It is hypothesized that the skin, the nervous system and immune system interact with one another to generate a cascade of physiological responses to the scraping, through which scraping may result in therapeutic benefits. Within the scope and limitations of this review, only a brief overview could be given of the potential relationship between the observed outcomes and scraping therapy. Implementing effective traditional healings within health systems will require appropriate knowledge translations and future prospective studies.

And they add the following ket points:

1. The observed therapeutic effects following scraping therapy may be a physiological response to the minor bruising.
2. Scraping is assumed to be a mechanical signal to elicit the immune function of the skin.
3. Through natural resolving of the scraping marks (petechiae) a cascade of physiological responses are generated.
4. Counterirritation and placebo effect can also contribute to positive effects for symptom relief.

I think that this paper is a good example for highlighting a common misunderstanding in so-called alternative medicine (SCAM): the confusion about how and whether any given therapy might work.

It is in my view utterly irrelevant, to consider or investigate the mechanisms of action of a SCAM that has not been proven to be an effective treatment of a disease or symptom. Such an approach can only lead to confusion about the value of the SCAM in question. In the present case, it makes gua sha look almost like a reasonable therapy, and consumers who read the paper might conclude that gua sha is worth trying.

A deliberately exaggerated example might make this clearer: If I fall down the staircase, a multitude of physiological effects of the fall could easily be verified on my body. Yet, nobody would claim that throwing patients down the stairs is of therapeutic value. Likewise, the forceful scratching of the skin is bound to have all sorts of physiological effects. These are, however, totally irrelevant until someone has shown that the procedure also has therapeutic value.

To put it bluntly: who cares how a SCAM works when it is unproven that it works?