Wiktionary
n. The treatment used in traditional Chinese medicine involving repeated pressured strokes over lubricated skin with a smooth edge.
Wikipedia
''Gua sha'' , 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 transferred and translated 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 expatriate 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, the coin is removed from the egg and will appear blackened.
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.
It was also used in India for treatment of high fever symptoms. People used metal spoon and water for skin lubrication.