Facial palsy (口眼喎斜, Guanwasa) is a condition in which the mouth and eye become drawn to one side, caused by paralysis of the facial nerve — the 7th cranial nerve.

When the body’s vital Qi (正氣) is weakened, external cold and wind invade the meridians, blocking the flow of Qi and Blood through the major meridians that pass through the face (such as the Stomach and Large Intestine meridians), so the muscles no longer receive proper nourishment.