Bi literally means “obstruction” in Chinese. Bi syndrome refers to a variety of conditions in which there is a painful obstruction to the normal flow of Qi and Blood. In general, Qi stagnation is less severe, and Blood stagnation is more severe. Bi syndrome can be caused by an external invasion of wind, cold, or damp. It can also be caused by a disharmony of the Zang Fu or by a traumatic injury. Joint and body pains are the conditions most commonly diagnosed as Bi syndromes, but the term applies to a variety of conditions, including chest pain and headaches.