Staging Bronchial asthma can be divided into 3 stages according to clinical manifestations: 1. Acute exacerbation (exacerbation): is a progressive exacerbation of shortness of breath, cough, wheezing, chest tightness or a combination of the above symptoms, characterized by a decrease in peak expiratory flow rate value (PEF), which can be quantified and monitored by pulmonary function tests (PEF or FEV1). It is often caused by exposure to irritants such as allergens or improper treatment. 2.Chronic persistent phase (persistent): It refers to the occurrence of symptoms (wheezing, shortness of breath, chest tightness, cough, etc.) at different frequencies and/or to different degrees every week. 3. Clinical remission period: It refers to the disappearance of symptoms and signs with or without treatment, and the return of pulmonary function to the pre-acute attack level, which is maintained for more than 3 months. Grading 1. Grading of severity: Schedule According to the frequency of daytime and nighttime asthma attacks and the measurement of lung function, there are 4 grades, namely ① intermittent attacks, ② mild persistent, ③ moderate persistent and ④ severe persistent. It is mainly used to judge the severity before treatment or at the time of initial treatment. Notes on clinical asthma severity grading according to the above table: daytime symptoms, nocturnal symptoms, and pulmonary function should be treated according to the higher level protocol as long as one of them reaches the higher level; ② If a patient is hospitalized for asthma within one year, he/she should be treated as severe asthma; ③ Asking the patient about the number of short-acting b2 agonists can help to grading correctly; ④ Pulmonary function tests are important in asthma grading. Grading asthma according to severity is useful in determining the initial treatment plan. However, it is important to recognize that the severity of asthma is related to both the current condition and its response to treatment. Thus, a patient with asthma who is initially classified as having severe persistent asthma because of severe symptoms and airflow obstruction is classified as having moderate persistent asthma because he or she responds adequately to treatment. In addition, the severity of an asthmatic patient is not static and can change over months or years. Because of these considerations, the classification of asthma severity based on expert opinion rather than evidence-based medical evidence is not advocated to continue to be the basis for deciding on treatment options, except in certain clinical studies where it still has value. Its main limitation is that it is difficult to predict what kind of treatment a patient needs? and how the patient will respond to treatment? For these purposes, periodic assessment of the level of asthma control is a more reliable and useful method.