In the clinic, I often encounter many patients with chronic coughs who have been coughing for two or three months, and have used all kinds of Chinese herbs, western medicine, antibiotics, and cough suppressants ……, but they are not well. Chest X-ray, CT, blood sampling, and laboratory tests …… have been conducted, but no major problems have been detected. The patient himself and his family were puzzled and nervous and decided that he might have cancer, asking the doctor to take a good look at what was going on with this cough. Cough is divided into acute, subacute and chronic At present, we usually classify cough into acute cough (less than 3 weeks), subacute cough (3 weeks-8 weeks) and chronic cough (more than 8 weeks). Acute coughs can be divided into two types: acute life-threatening coughs: such as those caused by pneumonia, asthma or chronic obstructive pulmonary disease, exacerbations, pulmonary embolism, heart failure, and other serious diseases. The second is non-life-threatening acute cough: such as infections (upper and lower respiratory tract infections), exacerbations of pre-existing diseases (asthma, bronchiectasis, upper airway cough syndrome and chronic obstructive pulmonary disease), and environmental and occupation-related acute cough. Subacute coughs are divided into post-infectious and non-infectious coughs. Post-infectious cough includes: cough caused by pneumonia or other serious diseases, whooping cough, bronchitis, and exacerbations of new or existing diseases (upper airway cough syndrome, asthma, gastroesophageal reflux, and bronchitis). Chronic cough is often underdiagnosed and misdiagnosed Common causes of chronic cough, in addition to smoking or angiotensin-converting enzyme inhibitors, include upper airway cough syndrome, asthma, eosinophilic bronchitis, and gastroesophageal reflux. Because chronic cough patients have few concomitant symptoms and no obvious abnormalities on x-ray, there are few diagnostic clues, and because physicians do not pay enough attention to them, they are often misdiagnosed and missed in clinical practice. In addition, these patients usually have their own specific etiological distribution. Many patients have been misdiagnosed as “bronchitis” or “chronic bronchitis”, and many of them have been suffering from the disease for several years, which seriously interferes with the patients’ daily life, study and work. Due to unclear diagnosis, these patients are either repeatedly treated with various antibiotics or repeatedly undergo various meaningless tests, resulting in a great waste of medical resources. The most common cause of cough is after a cold The most common cause of cough is after a cold. As the virus invades the upper respiratory tract, the secretion of mucous membrane in the trachea and nasal cavity increases and the patient develops runny nose, nasal congestion and phlegm. The throat, stimulated by the presence of phlegm, makes reflex actions such as contraction and coughing in order to clear the phlegm. This upper respiratory tract infection or infection of the lower respiratory tract can usually be cured with a few days of treatment. Coughing is actually a protective reflex of the body. When the upper and lower respiratory tracts are stimulated by excessive secretions, harmful gases, or foreign objects that mistakenly enter the airway, a persistent or strong cough is produced in an attempt to remove the foreign objects. However, frequent and prolonged coughing can affect the patient’s life, sleep, and even his or her respiratory and cardiac functions, making coughing of this nature a pathological condition. To cure a cough, one should first go in search of the cause of the cough. For post-infectious cough in adults (if it is not bacterial sinusitis or early Bacillus pertussis infection) the following is recommended: antibiotic treatment is not worthwhile, try inhaled ipratropium bromide. If the cough persists after ipratropium inhalation and affects the patient’s quality of life, consider inhaled adrenocorticosteroids. For coughing episodes following severe infection, short-term oral adrenocorticosteroids may be considered after excluding other causative factors. Central cough suppressants, such as codeine and dextromethorphan, should be used only if other methods have failed. There are six major causes of chronic cough There are many common diseases that cause chronic cough, such as chronic throat disease, chronic bronchial disease, and chronic lung disease. There are also several other diseases that are less familiar: upper airway cough syndrome, bronchial asthma, eosinophilic bronchitis, gastroesophageal reflux disease, chronic cardiac insufficiency, and drug effects. The first three of these diseases account for 90% of the causes of chronic cough. (1) Upper airway cough syndrome: This is a syndrome, not a specific disease, and the diagnosis needs to be determined by symptoms, signs, imaging and response to treatment. When inflammatory secretions from the nose and sinuses flow back into the throat or airways, coughing can occur due to irritation. We commonly see patients with rhinitis and sinusitis in the clinic who present to the respiratory department with poor success with symptomatic medications, and the diagnosis is confirmed only after follow-up history and detailed examination. Treatment for this is preferred to first-generation antihistamines or mucosal decongestants. (2) Bronchial asthma: generally episodes of wheezing and dyspnea. However, there is a special type of asthma, medically known as “cough variant asthma” or “cough asthma”, whose main manifestation is a persistent cough, mostly at night or in the early morning, sensitive to irritating odors, often with an irritating cough, and without croup on lung examination. Croup is often absent on lung examination. These patients are often misdiagnosed as having chronic bronchitis or chronic laryngitis, and their quality of life is seriously affected by the long-term use of antibiotics without relief. This cough has the following four characteristics: (1) the cough is mainly at night or in the early morning; (2) there is a prolonged dry cough with little sputum; (3) the cough is aggravated by cold air or irritating odors; and (4) the effect of prolonged antibiotic treatment is unsatisfactory. Such patients can be diagnosed by bronchial provocation test or dilation test. Treatment with inhaled hormones and bronchodilators can completely relieve cough symptoms. (3) Eosinophilic bronchitis: It is also one of the most common causes of chronic cough. (4) Gastroesophageal reflux disease: Gastroesophageal reflux can cause chronic cough is something that many people do not easily think about. According to the literature, chronic cough caused by gastroesophageal reflux disease accounts for about 20% of cases. This is due to irritation of the lower esophagus by the reflux entering the esophagus, causing abnormal nerve reflexes and resulting in respiratory spasms that produce a cough. If the patient often has symptoms such as acid reflux, heartburn, and foreign body sensation in the throat, and if the cough symptoms are associated with satiety, recumbency, sleep, and alcohol consumption, the cough should be considered as possibly related to a digestive disorder. Once the diagnosis is established, the doctor will treat the cough with appropriate medication or anti-reflux surgery, which can result in significant relief. (5) Chronic bronchitis: The cough of chronic bronchitis is characterized by a cough with a large amount of sputum coughed up, predominantly in the morning, and increased and purulent sputum with acute infection, which turns yellow in color. Chronic bronchitis often has a history of more than two years, and the cough lasts for more than three months each year. Its treatment, first of all, is to quit smoking, strengthen exercise, enhance physical fitness, and reduce the number of episodes of respiratory infection. (6) Drug effects: Many drugs can cause coughing, for example, commonly used drugs for hypertension, i.e. angiotensin-converting enzyme inhibitors, such as Kepone, Yuetinin and Lodinin; amiodarone and diuretics can also cause coughing. The cough can be relieved as soon as the medication is stopped immediately. Therefore, patients should be reminded to read the instructions carefully before using the medication to make sure that they are well informed. When it comes to cough, many people naturally think of respiratory diseases, but tend to ignore other systemic diseases. Cough receptors are not only found in the respiratory system such as the throat, trachea and bronchi, but also in the esophagus, paranasal sinuses, external auditory canal, pleura and pericardium, and lesions in these systems or areas may produce cough symptoms. Therefore, in addition to the respiratory system, attention should also be paid to lesions of the digestive, otorhinolaryngological, and cardiovascular systems. Cough is also associated with a history of specific occupational exposures, such as warehouse dust, dust mites, pollen, silk, mushroom spores, etc. Occupational exposure to chemicals or chemical products, such as rubber gloves and acrylic salts, has also been reported. Cardiac insufficiency can also manifest as cough, especially in those with wheezing after activity and paroxysmal dyspnea at night. According to Academician Zhong Nanshan, one of the main developers of the Guidelines, this Guideline will further standardize the diagnosis and treatment of cough, improve its success rate, save medical resources and ultimately benefit patients.