Asthma is a type of chronic desquamative bronchitis and, so far, the role of the bronchial epithelium in this disease has not been fully assessed. There are at least 3 ways by which bronchial epithelial cells may modulate the pathophysiology of asthma: 1. They are resident cells, capable of liberating pro-inflammatory mediators, which may be chemotactic for other cells such as neutrophils and eosinophils. 2. An asthmatic attack results in desquamation of the bronchial epithelium which may have multiple consequences. 3. A repair phase must follow the desquamation although the precise mechanisms underlying this phase are incompletely understood. The level of reparation is likely to play an important role in the prognosis of the disease.