We have earlier shown epithelial damage in the airway mucosa in patients with asthma. Later other structural changes have been recognized in asthma, such as deposition of collagen and tenascin in the subepithelial basement membrane and changes in the laminin subchain composition. These processes are modified by an inflammatory process in the airways. Both the United States National Institutes of Health and the British Thoracic Society guidelines on the management of asthma emphasize the need for early use of anti-inflammatory drugs. Many clinical studies that used airway biopsy specimens have shown a decrease in airway inflammatory cell numbers after inhaled corticosteroid therapy. However, there is very little information on the effects of asthma medication on the structural components of the airways. Both the synthesis and degradation of many extracellular matrix components may be affected by the disease process and the drugs resulting in altered remodeling and gene expression in the airways. Because there are only a few studies that try to identify early changes in asthma, it is not known whether the anti-inflammatory treatment of asthma proposed by the guidelines is started early enough.