Sneezing refers to an unconscious "reflex" when a foreign body (such as dust, bacteria, pollen, etc.) occurs. ) I was driven away when I entered the nasal cavity. After the foreign body enters, the trigeminal nerve located on the nasal mucosa sends instructions to the respiratory muscles acting on the lungs, violently expelling the air and expelling the foreign body from the country. Sneezing reflex, commonly known as "sneezing" or "sneezing", is a defensive reflex action caused by nasal mucosa stimulation. However, in traditional folk customs, it has been regarded as a sign of some abnormal behavior or the development trend of things, and various explanations for it make people fall into a fog.