A term 'bronchial hyperreactivity' refers to abnormally strong bronchospasm caused by many various factors that in normal conditions are not able to produce such response. In practice the assessment of bronchial reactivity is based on bronchial challenge tests. The aim of our study is to present currently used bronchial provocation tests, consisted of assessment of initial pulmonary function parameters, administration of a bronchospastic challenging agent, measurement and interpretation of observed changes. Histamine and methacholine are the most commonly used provocation agents. Safety, usefulness, nonallergenic activity of these agents allows obtained results to be repeatable. Bronchial provocation tests may be used to confirm existing bronchial hyperreactivity but also to evaluate 'severity' of asthma and its response to pharmacological treatment. Positive tests correspond with diagnosis of asthma but have less diagnostic value because they can also be positive in several other diseases such as e.g. COPD, cystic fibrosis, bronchiectasis, sarcoidosis, viral respiratory tract infections, heart failure or reflux oesophagitis. Provocation tests are particularly important in cases of bronchial asthma clinically manifested by cough without wheezing and flow limitation syndrome. Properly performed bronchial provocation tests are safe. Relative contraindications may be diagnosed: history of unexplained urticaria or Quincke's edema, severe airflow obstruction, unstable angina and pregnancy. If initial results of spirometry are normal, bronchospasm will spontaneously regress within 30-45 min. or even within 5 min. after administration of bronchodilators. Symptoms including cough, chest discomfort, breathlessness, sore throat, excessive salivation, headache and dizziness are usually mild and last for several minutes.

Keywords: methacholine, Asthma, Bronchial Hyperreactivity