Many parents of children with cough and asthma have this question in mind: Why does the doctor want my child to inhale hormones? Here is a scientific explanation for parents: I believe that many parents have the experience that their child was fine and then had a recurrent cough. This is because the cough was caused by a viral infection and induced airway hyperresponsiveness. Airway hyperreactivity is essentially the result of the body’s own response to a viral infection. When the respiratory tract is infected with a virus, inflammatory cells such as lymphocytes from the body gather in the infected respiratory tract to fight the virus. The inflammatory cells involved in the antiviral process produce substances such as histamine, leukotrienes and many other substances called “inflammatory mediators”, which are involved in the fight against the virus and also affect the respiratory tract tissues, resulting in airway hyperresponsiveness. What is even more incredible is that this respiratory response to the virus does not disappear when the virus is cleared, and inflammatory cells such as lymphocytes continue to exist and continue to produce inflammatory mediators. Therefore, airway hyperresponsiveness after a single viral infection can last up to 3 months. To treat this type of cough and wheeze, we should treat airway hyperresponsiveness, and to treat airway hyperresponsiveness, we should target the lymphocytes and inflammatory mediators involved in the disease. Nowadays, there are drugs for histamine and leukotrienes, but due to the large number of inflammatory mediators involved in this pathological process, antihistamine and leukotriene antagonism alone are not enough to effectively control the disease. Currently, the only drug that is effective against all inflammatory mediators is adrenal glucocorticoids, commonly known as “hormones”. Therefore, hormone therapy should be chosen for the treatment of cough and asthma with airway hyperresponsiveness. However, hormone therapy has a major shortcoming, because when hormones are used orally or by injection, most of the drugs are distributed throughout the body, and only a small amount of the drugs are effective in the respiratory tract, and long-term use has obvious side effects, while long-term hormone therapy is needed to treat this type of cough. In order to solve the contradiction between efficacy and side effects, there is the current surface hormone inhalation therapy. The characteristics of surface hormone inhalation therapy are: strong local anti-inflammatory effect of the drug, less systemic reaction; inhalation of the drug acts directly on the patient’s site, and the dose of the drug is small, thus obviously reducing the side effects of long-term use of hormones on the body, and achieving the purpose of safe and effective treatment of such cough and asthma.