Cough is also one of the common clinical symptoms of asthma and is a specific manifestation of the presence of airway inflammation and airway hyperresponsiveness. In northern areas of China, including northern and northwestern China, and even northeastern China, pollen allergy is common in autumn. The most allergenic are plants of the genus Artemisia and a few ragweeds and grasses. Diagnosis can usually be determined by going to the hospital for allergen testing and bronchial excitation tests. Prevention is achieved by regular use of asthma control medications, such as inhaled appropriate doses of glucocorticoids, for half to one month prior to the onset of the season. If the disease is severe, a combination therapy may be used, combining inhaled hormones with another controlling medication, such as a long-acting beta2 agonist, as is often the case. If the patient is not diagnosed early and treated effectively, the asthma may initially be seasonal and persist for many years and may become perennial as the pathological changes of asthma (including airway inflammation, airway hyperresponsiveness) are not effectively controlled and therefore require special attention.