Gua sha (Chinese: 刮痧; pinyin: guā shā), meaning "scraping sha-bruises", is a traditional Chinese medical treatment in which the skin is scraped to produce light bruising. Practitioners believe gua sha releases unhealthy elements from injured areas and stimulates blood flow and healing. Gua sha is sometimes referred to as "spooning" or "coining" by English speakers, it has also been given the descriptive French name, tribo-effleurage.
Gua sha was borrowed into Vietnamese from China as cạo gió. This term translates roughly "to scrape wind", as in Vietnamese culture "catching a cold" or fever is often referred to as trúng gió, "to catch wind". The origin of this term is the Shang Han Lun, a ~220 CE Chinese Medical text on cold induced disease - like most Asian countries China's medical sciences were a profound influence in Vietnam, especially between the 5th and 7th Centuries CE. Cạo gió is an extremely common remedy in Vietnam and for overseas Vietnamese. There are many variants of cạo gió. Some methods use oil balm and a coin to apply pressure to the skin. Others use a boiled egg with a coin inserted in the middle of the yolk. The egg is wrapped in a piece of cloth and rubbed over the forehead (in the case of a fever) and other areas of skin. After the rubbing, when the coin is removed from the egg, it will appear black.
It is also used in Indonesia, and in Java it is known as kerikan (lit., "scraping technique") or kerokan, and it is very widely used, as a form of folk medicine, upon members of individual households.
Gua sha involves repeated pressured strokes over lubricated skin with a smooth edge. Commonly a ceramic Chinese soup spoon was used, or a well worn coin, even honed animal bones, water buffalo horn, or jade. A simple metal cap with a rounded edge is commonly used.
In cases of fatigue from heavy work, a piece of ginger root soaked in rice wine is sometimes used to rub down the spine from head to feet.
The smooth edge is placed against the oiled skin surface, pressed down firmly, and then moved down the muscles—hence the term tribo-effleurage (i.e., friction-stroking)—or along the pathway of the acupuncture meridians, along the surface of the skin, with each stroke being about 4–6 inches long.
This causes extravasation of blood from the peripheral capillaries and may result in sub-cutaneous blemishing (ecchymosis), which usually takes 2–4 days to fade. Sha rash does not represent capillary rupture (petechiae) as in bruising, as is evidenced by the immediate fading of the markings to echymosis, and the rapid resolution of sha as compared to bruising.
Cross-cultural confusion with physical abuse
A slightly different form of gua sha using the edges of coins rather than porcelain items is practiced as a folk medicine technique. Individuals practice this "coining" amongst their own family members in many Asian cultures, such as Vietnam (where the coin scraping, or "coining" is known as "cạo gió", 'scraping for wind'), in Cambodia, and in their respective immigrant communities abroad. For example, health care practitioners in hospitals in Orange County, California, routinely see evidence of coining among hospitalized Vietnamese patients.
Physicians are required by law to report injuries from remedies such as "coining" to the appropriate agency (e.g., state child-protective service or state adult-protective service), regardless of intention. 
- Huard & Wong (1977), p.126. They also cite a French romanization for the same set of two Chinese characters: koua sha.
- Needham, J., Celestial Lancets, Cambridge, UK: Cambridge University.
- One of the first to introduce the technique of gua sha to non-Chinese students in the United States was James Tin Yau So (1911 - ).
- Fadem, Barbara (2009). Behavioral Science - Board Review Series. Baltimore, MD: Lippincott Williams & Wilkins. p. 206. ISBN 978-0-7817-8257-9.
- Huard, P. & Wong, M. (Smith, D.N. trans.), Oriental Methods of Mental and Physical Fitness: The Complete Book of Meditation, Kinesitherapy, and Martial Arts in China, India, and Japan, Funk & Wagnalls, (New York), 1977. ISBN 0-308-10271-1
- Nielsen, A., Gua Sha: Traditional Technique for Modern Practice, Churchill Livingstone, (Edinburgh/New York), 1995. ISBN 0-443-05181-X
- Nielsen, A., "Gua Sha. Step-by-Step: A Visual Guide to a Traditional Technique for Modern Medicine" (teaching video)Verlag fuer Ganzheitliche Medizin, Koetzing, Germany. 2002. ISBN 3-927344-63-X
- Yeatman GW, Dang VV. Cao gio (coin rubbing): Vietnamese attitudes toward health care. JAMA. 1980;244:2748-2749