There is another kind of asthma that is easily ignored by doctors and patients, patients only show cough, usually with dry cough or a small amount of white sputum, often when smelling special odor, oil smoke, cold air, cough aggravated, some patients cough aggravated at night, taking cough medicine is ineffective, patients who continue to cough for more than two months need to be alert, such patients should do a bronchodilator test, the value of this test is greater than 12% but the absolute value of FEV1 is greater than 200 ml is relevant for diagnosis. If the bronchodilator test is negative, the patient is advised to have a bronchial provocation test, which has the same significance if it is positive. We call this cough allergic cough or cough allergic asthma. Some patients with cough need to have induced sputum examination if necessary and bronchoscopy has been done to clarify the diagnosis for appropriate treatment.