Numerous recent studies point out a relationship between bronchial reactivity and the inflammation of the airways. The paper deals with the most frequent mechanisms of bronchoconstriction in occupational asthma combined with inflammatory process. The importance of inflammation in the Moira Chan-Yeung classification of occupational asthma is emphasized. According to this classification several types of occupational asthma are associated with the working environment. It is stressed that continuing prophylaxis of inflammation should protect the worker from irreversible airflow obstruction. This is of special interest to the population suffering from occupational asthma.