Coin Rubbing Part 1: Introduction

Known in Khmer as កោស​ ខ្យល់ (koah kshal - scraping the wind), in Vietnamese as Coa Gio (catch the wind), in Chinese as Gua Sha (scraping away fever), and in Indonesian as Kerokan (scraping technique), coin rubbing is a healing technique practiced in most of southeast Asia as well as some prominent east Asian countries. In Cambodia it is practiced by virtually everybody. The people I have talked to about the practice have never met another Cambodian who didn’t “believe” in coin rubbing. It is practiced both in families and professionally. Going down most roads in Phnom Penh you should eventually run into signs that advertise for 5000r massages.

While the practice and its explanation differ according to region, there are some important commonalities. The procedure always involves a type of oil or ointment and a hard circular disk, usually a coin. My experience has been almost exclusively with tiger balm but any oil containing combinations of camphor, methanol, winter green oil, eucalyptus oil, peppermint oil or cinnamon oil (taken from here citing Sullivan, 2005). My wife claims that before the magical introduction of tiger balm her family used machine oil. The oil is applied and a coin is rubbed until red marks, blood under the skin, becomes visible. In my experience, the lines are rubbed on either side of the spine (or directly down the middle) and then in horizontal lines down the back. If pain is serious enough it can also be done on the whole body (head, neck, chest, arm, legs). Sometimes it is only done in the local area of the pain or soreness. It is supposed to be able to cure insomnia, migraines, headaches, cramps, muscle soreness, respiratory problems, chronic pain, chronic cough, carpal tunnel, joint problems, whiplash, diarrhea, other stomach related problems, fevers, urinary disorders and probably a whole range of other symptoms.

Different hues and boldness of color can often be used as a diagnostic tool. I have heard different interpretations but my wife’s family generally follows a simple pattern. If the red of the blood is light, it is a light illness. As the red increases in intensity, so does the illness. Some people’s skin however, don’t show these fluctuations.

The lay explanations I have heard justifying the procedure generally rely on the idea of bad wind or miasma being the root of illness. The rubbing and breaking of blood vessels allows this miasma to leave from the body. Sometimes this is framed as an imbalance. As the practice probably comes from China some have linked it to yin and yang. Balance is an important part of all medical systems, and was even was the dominant paradigm of the western medical system before the 1900’s. It is an explanation that is intuitive and can be understood quite easily. Other explanations involve increasing blood circulation and breaking down toxic blood clots.

In the United States, Southeast Asian communities still practice coin rubbing but have run into problems with schools and medical professionals mistaking the marks for abuse. Proponents claim that it causes no long term harmful effects and is an attempt to heal a child from a loving parent. There is currently increased awareness of the cultural practice and the instances of these accusations have decreased. Despite this awareness however there is no actual acceptance of the practice as a legitimate healing method among western health professionals. In Cambodia the dissonance between what educated professionals are taught and what their families and patients practice is ignored but I can see it developing into a problem in the future. The scientific community cannot accept coin rubbing as legitimate practice for two reasons. The first is that it’s premise, that illness is caused by miasmas, has not been proven in a repeatable way in a laboratory. The second reason is that there are no studies showing that it effects pathways in the western physiological model of the body.       

I have heard a variety of lay explanations of how coin rubbing may be able to fit into a western model of medicine. They include the distraction of pain, a release of endorphin, muscle relaxation, bringing blood to the surface to cool down fevers, increasing white blood cells counts and, of course, the placebo effect. I'm not a huge fan of the placebo effect as a blanket explanation for anything and I may write more about the later. I think it is used too often to explain away results that we do not fully understand. Some or all of these may have an effect but unless someone forms a quality repeatable experiment it will all be guesswork. Coin rubbing may not have any real physiological benefit or it may use pathways that we have not yet begun to understand. Personally I think that there is a lot to learn from traditional medicine and that until it is fully understood, it needs to be taken with a degree of seriousness. I am also aware that popular use does not necessarily mean it is a positive procedure, as blood letting was at one point quite popular and has since been shown to be a negative experience.

For my next two posts I want to explore recent literature which may or may not show physiological benefits and physiological damage cause by the practice.

As always, feel free to comment with your own experiences and thoughts about coin rubbing.