Cao gio is a technique incorporated into the practice of Traditional Chinese Medicine (TCM). It is pronounced as gow yaw and better known in English as coining. Coining is widely practiced in particular by Southeast Asians, such as the Vietnamese, Thai, and Lao. Coining treatment involves a coin repeatedly rubbed against an area of the skin in long flowing moves, which always move away from the heart. Blood begins to rise to the surface of the skin, and will leave a mark that resembles a bruise. The areas of the body that are most frequently treated are the back and ribs, and the marks will fade a few days after the treatment is over.