Nocturnal asthma-especially night cough are sometimes the first and only symptom of the beginning disease in childhood and are then often misinterpreted. The cause of nocturnal asthma seems to be a circadian rhythm of hormones and mediators, much more predominant in asthmatic than in healthy children. Moreover, there are some evidences, that also other factors--i.e. inflammation, number of T-helper cells and beta-receptors, allergen contact a.o.--influence this process leading to a deterioration of bronchial reactivity and lung function. Furthermore children with stable asthma show a prolonged expiration time during sleep compared to healthy children. Nocturnal asthma calls for an intensification of therapy. Besides the removal of allergen sources (HDM) and a warranty of free upper airways (adenoids), drug therapy should be optimised. This applies for the basic antiinflammatory treatment as well as for the use of long acting bronchodilators. The relatively high demand for beta-agonists in children and the age dependence of half-life for theophylline must be considered.