Cough is one of the most common symptoms of respiratory diseases and is also an important defensive respiratory reflex. When coughing, a short and deep inspiration occurs, followed by a tight closure of the vocal folds and a strong expiratory movement, causing both intrathoracic and intrapulmonary pressures to rise rapidly. Afterwards, the vocal chambers suddenly open, and due to the great pressure difference, gas is ejected from the alveoli at a very high rate, expelling foreign bodies or secretions present in the airways. As strong and persistent coughing can cause a significant increase in intrathoracic pressure and reduce venous blood return, it may have adverse effects on the body, such as pneumatic injuries, syncope, vascular rupture, fracture, urinary incontinence and mental distress, syncope, etc. Long-term chronic cough can cause a decrease in the elasticity of lung tissue due to a continuous increase in intrapulmonary pressure and cause an increase in pulmonary circulatory resistance, which is an important cause of the formation of emphysema and pulmonary heart disease. From an academic point of view, acute cough is defined as less than 3 weeks; subacute cough is 3 to 8 weeks; and a course of more than 8 weeks is considered chronic cough. The treatment of chronic cough is so tricky that Xu Lingtai, a famous doctor in the Qing Dynasty, said, “I have been studying this evidence for more than 40 years before I could do anything about it. Although this is a modest statement, it also explains to a certain extent the difficulty of treating it. When a chronic cough is persistent and conventional cough treatment is ineffective, the general idea is to first look at a chest x-ray. If there is a positive finding on the chest X-ray, the cause (such as anti-inflammatory, anti-TB, anti-tumor, etc.) should be treated or further examined as appropriate; if the chest X-ray and other tests are “negative”, the following aspects should be considered to identify the treatment. (1) Cough caused by “fever”: If a dry cough is the main or only symptom of a cough for more than 3 weeks, and conventional treatment is still not effective, and there are no abnormalities in routine blood and chest X-ray examinations, the first consideration should be post-cold cough (also called post-infectious cough). It is characterized by a cough that persists even after the symptoms of the acute phase such as fever have disappeared, and does not improve even after long-term or repeated antibiotic treatment. We classify this kind of cough after an external heat illness as “cough caused by heat”. The treatment in TCM is based on the principle of diagnosis and treatment. Those with clear and white sputum, stuffy and runny nose, sneezing, cold and no sweat, and headache belong to the wind-cold attack on the lung, and should be treated with Xing Su San plus or minus; those with excessive sputum, fullness in the chest and epigastrium, poor appetite, and weakness in the limbs belong to the phlegm and dampness in the lung, and should be treated with Er Chen Tang or Liu Jun Zi Tang plus or minus; those with a cough with rebellious qi, difficult or little sputum, pain in the chest and hypochondrium, irritability, and redness of the face and eyes belong to liver fire. If the cough is persistent, with dry mouth and dry tongue, irritable heat in the five hearts, flushing and night sweating, it belongs to deficiency of lung yin, so use Sha Shen Mai Dong Tang with addition and subtraction. (2) Cough caused by “nose”: postnasal drip syndrome is another common disease causing chronic cough, which is now named “upper airway cough syndrome”. It is characterized by episodic or persistent coughing, mainly during the day and less after sleep; postnasal drip and/or a feeling of mucus adherence to the posterior pharyngeal wall; a history of rhinitis, sinusitis, nasal polyps, or chronic pharyngitis; and an examination that reveals mucus adherence to the posterior pharyngeal wall and a cobblestone-like appearance. Cough caused by the common cold may also be caused by postnasal drip irritation. The common cold can be considered as a postnasal drip syndrome. Since the common cold is the most common disease in humans, postnasal drip syndrome is one of the most common causes of cough. In recent years, the incidence of this disease has increased due to climate change, increased atmospheric pollution, the stacking of cold medicines and the abuse of antibiotics. The cough is reduced or disappears after the administration of paracetamol ephedrine combination or hormonal nasal drops. Treatment can be based on the above principles of identification of cough caused by “heat”. (3) Cough caused by “stomach”: Cough caused by gastroesophageal reflux is also easily misdiagnosed and accounts for about 40% of chronic coughs. It is often accompanied by heartburn, acid reflux, chest pain, nausea and other digestive symptoms. 24H esophageal PH monitoring is diagnostic. The mechanism is unclear and may be related to irritation of cough receptors in the pharynx, larynx and trachea by refluxed material. It can be rapidly alleviated by the use of acid-suppressants or gastrointestinal stimulants (e.g. morpholine) or H2 receptor blockers, proton pump inhibitors, but significant improvement takes up to 5 months. Chinese medicine treatment can be started from the perspective of draining the liver, regulating qi and stomach. (4) Cough caused by “wheezing”: This “wheezing” is not the same as the other “wheezing”, but has the substance of wheezing without the manifestation of wheezing. If the cough has been present for more than 2 months, the possibility of cough variant asthma should be considered. Both have cough as the only or main symptom and no significant abnormality on chest X-ray, and both have periods of self-remission. The former often has allergic diseases such as urticaria, skin eczema, and allergic rhinitis. Allergen skin tests are often positive for one or several antigens. The nature of their cough is different. The former is unusually violent, persistent and unresolved, with a paroxysmal spasmodic dry cough, occasionally with a small amount of mucous sputum, with nocturnal or morning onset, affecting sleep, aggravated by cold air or induced by exercise, and ineffective anti-inflammatory and phlegmatic cough suppressants. Positive bronchial excitation test or diastolic test. According to the clinical manifestations of cough variant asthma, it belongs to “wind cough” caused by loss of lung qi, unfavorable lung ducts, and contracture of airways in traditional Chinese medicine. The medicine “Su Huang Cough Capsules” is also used. In addition to the above, there are several other causes of cough. Many interstitial lung diseases often have dry cough as the main symptom in the early stage, in which case pulmonary function tests can help in early detection; drug-induced cough is commonly caused by ACEI (Kepone) and B-blockers, with an incidence of about 15%. It occurs 24H or several months after taking the drug. More females than males. May be related to increased sensitivity of cough receptors. Removes after several days to 4 weeks of discontinuation; after excluding these factors, psychogenic cough can be considered, associated with negative emotions such as stress, anxiety, and sadness. It is characterized by a dry cough, which is not loud, like the sound of “geese”. It is easily interrupted by speech and does not cough at night. Dietary remedies for chronic cough: (1) Green leafy vegetables, animal offal, egg yolk, milk, etc. (2) 150 grams of olives, 500 grams of radish, decoction for tea. (3) Salt smothered pig heart: 1 fresh pig heart, a small amount of water in the pot, salt covered, fire smothered for 1 hour to eat, 1 or 2. (4) Honey steamed pear.