Asthma is a chronic disease of the respiratory tract, which is essentially a metabolic inflammatory disease rather than an infection. The attacks are characterized by recurrent coughing, wheezing, chest tightness and dyspnea, which are more pronounced at night and early in the morning. The most effective medication for asthma is glucocorticoids. The Global Initiative for Asthma Control (GINA) divides asthma into four levels of severity according to the severity of the attack, like a ladder, with different doses and types of medication for each level. After a period of stable treatment in one of these levels (usually 3 months), the treatment is downgraded, and the other way around, the treatment is upgraded to ensure that the treatment of asthma is carried out according to a strict procedure to achieve complete control. The severity of asthma attacks is classified into four levels according to the condition: Class I (intermittent attacks): no asthma symptoms during the day can be maintained for a week, nighttime attacks more than 2 times a month, PEF ≥ 80%. Grade II (mildly persistent): daytime asthma attacks at least once a week but not necessarily every day, attacks that may interfere with activity, nighttime attacks more than twice a month, and PEF ≥ 80%. Grade III (moderate persistent): daytime attacks every day, asthma attacks that interfere with activity, nighttime attacks more than 1 time per week, PEF 60 to 80%. Grade IV (severe persistent): persistent symptoms during the day, limited physical activity, frequent attacks at night as well, PEF ≤ 60%. PEF (peak flow rate): the maximum expiratory volume in the shortest time is measured by portable peak flow rate meter, which can indirectly reflect the airway function of asthma patients.