Clinical exploring study of Weiyang Yuping Decoction in preventing acute attacks of mild to moderate intermittent asthma Based on the theory of "Preventing disease from exacerbating" in Chinese medicine.

Based on the preliminary clinical and basic research, this project intends to highly optimize and integrate the TCM treatment of disease theory with the current methods to form two preventive treatment plans, one treatment group was given Weiyang Yupingfang Granules orally for 1 month on the "Sanfu"days and on the "Sanjiu" days each year for a total of 2 months one year; the other treatment group was given Weiyang Yupingfang Granules orally for 1 month in the first month of each quarter in the four quarters of the year, for a total of 4 months one year.; Comparing the effect of prevention and treatment of mild to moderate intermittent asthma exacerbations of the two prevention methods , provides new ideas for the prevention and treatment of bronchial asthma in the future, and further improves bronchial The level of prevention and treatment of asthma.

Inclusion Criteria:

• Diagnosis of asthma according to GINA criteria with a documented history of at least 3 years prior to Visit 1
• Patients have asthma exacerbations every year
• Meet the diagnostic criteria for mild to moderate asthma
• Able to measure lung ventilation function according to ATS (American Thoracic Society) standards
• Patients who have given written informed consent

Exclusion Criteria:

• Medical history of life-threatening asthma including intubation and intensive care unit admission
• Any significant disease or disorder (e.g., cardiovascular, pulmonary other than asthma, gastrointestinal, hepatic, renal, neurological, musculoskeletal, endocrine, metabolic, malignant, psychiatric, major physical impairment) which, in the opinion of the investigator, may either put the patient at risk because of participation in the study, or may influence the results of the study, or the patient's ability to participate in the study
• Pregnancy, breast-feeding or planned pregnancy during the study.
• Participation in another clinical study or took other research drugs during the last 30 days prior to Visit 1
• Known or suspected hypersensitivity to study drugs or excipient
• Suspected poor capability, as judged by the investigator, of following instructions of the study.