[The hypersensitive respiratory system in childhood].

Aetiological factors and mechanisms of bronchial hyperreactivity are discussed. The hypothesis of increased permeability of the bronchial mucosa--caused by either endogenous or exogenous stimuli--as the most plausible explanation for the connection between hyperreactivity and childhood asthma bronchiale is emphasized. Finally, unspecific inhalative provocation tests for proof of bronchial hyperreactivity, its indications and contraindications as well as the criteria of judgement are mentioned.