Positive bronchial provocation test for cough variant asthma. Cough variant asthma belongs to a special type of asthma, although cough as the main symptom, but the essence of its pathology is also airway inflammation and to a variety of stimuli leading to increased airway responsiveness, reversible airway obstruction. Bronchial excitation test is to induce airway smooth muscle contraction through artificial stimulation, and with the help of changes in lung function indicators to determine whether the bronchial tube is narrowed. Positive bronchial provocation test is the main physiopathological characteristics of asthma, so cough variant asthma do bronchial provocation test is positive. Cough variant asthma is characterized by a cough, often without significant chest tightness or shortness of breath, which requires a bronchial provocation test to make a definitive diagnosis. Bronchial provocation test is a small amount of allergens to trigger a mild onset, there is a certain degree of risk, must be in a certain conditions of medical institutions, by a specialist doctor to carry out.