Coughing is a response of the respiratory tract to external or internal stimuli, just as tears flow when sand gets into the eyes or vomiting when you eat unsuitable food. The whole respiratory tract, from the throat to the trachea and then to the lungs, coughs to expel the “invading enemy” or “own bad elements” from the body. The most common form of acute cough is the “cold” and almost no one is immune to it. “In a cold, a virus invades the respiratory tract and makes a mess of the nose, throat and trachea. The human defense forces (white blood cells, various inflammatory factors) begin to charge into battle and fight with the incoming enemy, and the battlefield is a mess (snot, phlegm), and the respiratory tract discharges this “mess” by coughing. When we are victorious, the battlefield is cleaned up and the “cougher” can go home and rest. In some cases, the situation is more complicated, where the battlefield is apparently smooth (no obvious problems are found on chest X-ray), but the coughing does not stop, and various cough medicines do not work. If the cough is more than 8 weeks old (here it is a cough of a more severe degree; frequent throat clearing in chronic pharyngitis does not count), an X-ray of the lungs needs to be considered, and a high-resolution CT scan of the chest is superior to a plain chest X-ray. This test is a watershed, and if tumors, tuberculosis or other specific problems are found, then treatment is targeted, while if no obvious problems are found in the lungs after the X-ray, then the cause should be investigated, otherwise relying on antibiotics and cough suppressants will not have satisfactory results. These are the top four most common causes of chronic cough in all regions of the world, with the causes changing from region to region. The ranking may change. Some patients have only one of these factors, while others will have two or even three causes at the same time, especially if the first three are present in a single person, which I encounter several times a month at the clinic. Regardless of how many there are, these etiologies do not respond well to antibiotics and cough suppressants, and the only way to effectively control the cough is to use treatment that is specific to the respective etiology. For example, cough allergic asthma is mostly at the top of the list of reported cases in China, and treatment is similar to that of bronchial asthma, which requires allergen screening, anti-allergy and desensitization therapy. Gastroesophageal reflux is a very insidious one of these common causes. Academician Wang Zhonghao, a member of the vascular surgery community in China, himself had many episodes of coughing, shortness of breath, and laryngeal spasms, several times even to the point of resuscitation, tossing and turning for years before finally discovering that the root cause of the disease was caused by gastroesophageal reflux, and never had another serious attack after allopathic treatment. The diagnosis of this disease is so tortuous for the academicians in the medical field, so one can imagine how many ordinary patients are not detected in time. Most of the diseases with the “chronic” label are difficult to treat, mainly because the cause of many diseases is difficult to detect or impossible to solve even if it is detected. This is also true for chronic cough. The above list is only the top four causes that are currently recognized by the medical community as having the highest incidence, but fortunately, there are ways to control these four causes. There are some rare causes of chronic cough that need to be carefully investigated by doctors specializing in respiratory, otorhinolaryngology and gastroenterology. When the cause is not clear, it is pointless to talk about treatment.