Asthma is a chronic inflammatory disease of the airways involving the activation of many different cell types. The immunologic basis of asthma is widely accepted for allergic asthma, and the synthesis of IgE is dependent on cytokines. A process of healing and repair follows on from inflammation and this leads to a variable degree of remodelling of the airways. The treatment of asthma should take into account that the disease is associated with short-lived symptoms that can be prevented or reversed by bronchodilators, exacerbations that can be treated or reversed by anti-inflammatory drugs, and remodelling of the airways, for which no definite treatment has yet been validated.