Αsthma is a chronic inflammatory disease of the airwaysa and a lot of progress has been made in the understanding of its pathogenesis. Yet, there are many points that need further clarification and among them Holgate’s theory regarding the reactivation of the epithelial-mesenchymal trophic unit is of great interest. Epithelial cells under the influence of various stimuli secrete mediators, which affect mucous glands and myofibroblasts of the mesenchymal layer. The final result is permanent structural alterations of the airways, otherwise known as remodelling. This theory offers new target research areas in the therapy of asthma. Pneumon 2006; 19(4):339-348.