Bronchial asthma is a common chronic respiratory disease. Patients usually manifest variable symptoms (such as short of breath, chest tightness, cough, etc.) and variable airflow limitation and often associated with airway hyper-responsiveness and airway inflammation. About 1-18% of the global population suffered from the disease, causing huge economic burden for patients and countries. Airway reactivity measurement is an important way of diagnosis of asthma. Methacholine (Mch) bronchial provocation test(BPT) is the "gold standard" for the determination of airway reactivity, and other measuring methods(like adenosine monophosphate(AMP)-BPT, leukotriene D4(LTD4)-BPT, Astograph-BPT, etc.) were also brought into hot research fields. The investigators' purposes were to compare different kinds of methodologies(Mch,AMP,LTD4-BPT, Astograph-BPT) assessing airway responsiveness and to investigate treatment efficacy of budesonide /formoterol in asthmatics.

This study composed of two parts, that were the diagnosing part and the treatment part.

Inclusion Criteria:

• Clinically diagnosed Asthmatic patients aged from14 to 65 years；
• Had a had a normal chest radiographic result；
• Had a baseline spirometry with the forced expiratory volume in one second (FEV1) of not less than 60% predicted；
• Without acute upper respiratory tract infection for the past 2 weeks

Exclusion Criteria:

• Smokers；
• Had a poor cooperation to the test or limited understandings;
• Had a past confirmed history of respiratory disease other than bronchial asthma (COPD, bronchiectasis, pulmonary thromboembolism, etc.) or other severe systemic disease（myocardial infarction, malignant tumor, etc.）;
• Pregnancy or breast-feeding women;
• Taken related drugs before measurements（Leukotriene receptor antagonists (LTRA) for 5 days，oral glucocorticosteroid or anti-histamine for 3 days，oral xanthenes or long-acting bronchodilators for 2 days，inhaled corticosteroid or long-acting bronchodilator for a day , short-acting bronchodilator for 4 hours ）