The nose is located in the center of the five senses and is medically divided into three parts: the external nose, the nasal cavity and the sinuses. The external nose is protruding from the center of the face and resembles a three-pronged cone with its base downward; the nasal cavity is the cavity between the two sides of the face and skull, with complex anatomical structures in the nasal cavity, such as the nasal septum, upper, middle and lower turbinates, etc.; and the sinuses are air-containing cavities around the nasal cavity and hidden in the skull, with four pairs, namely the maxillary sinus, sieve sinus, frontal sinus and butterfly sinus, all of which have sinus openings and nasal cavity connections. As we all know, the nose is the passage of airflow in and out of the body when breathing, and it is also the organ of the body to feel the sense of smell. However, in addition to respiratory and olfactory functions, the nose has some important functions that are not well known: protective functions: nasal hairs can filter some larger particles in the air; smaller particles can settle in the mucus blanket secreted on the surface of the nasal mucosa and be sent to the pharynx by cilia swinging to swallow or spit out; reflex sneezing can expel some foreign bodies and particles that are inhaled; blood sinuses and glands under the nasal mucosa can warm and humidify the air; the mucus blanket can also be used to warm and humidify the air. Humidification; mucus blanket also contains some lysozyme, interferon, secretory IgA and other antiviral and bacterial substances. The nasal cavity is the first fortification of the respiratory tract, protecting the health of the body. Pronunciation and resonance function: Normal nasal cavity and sinus structures play an important role in the pronunciation of specific syllables such as m and n and the resonance of sound. Patients with nasal obstruction or nasopharyngeal cavities that do not close properly will have altered voice properties. Absorption function: The nasal mucosa is rich in blood circulation and absorbs drugs rapidly. Transnasal drug delivery can be used for the treatment of diseases such as respiratory diseases. Reflex function: The nasal mucosa can produce a series of reflexes after being stimulated, such as nasopulmonary reflex, nasocardial reflex, olfactory reflex, etc. causing coughing, sneezing, heart rate slowing, saliva, gastric juice secretion changes and other effects. Other functions: the nasal cavity is a channel for tear drainage; the presence of sinuses can reduce the weight of the skull and maintain the balance of the head, etc. Although the nose is small, it has many functions. In our daily life we should pay attention to protection and overcome bad habits such as plucking nose hairs and snapping nasal cavity to make it serve better for human health!