The authors compared the results of mycologic examinations of asthmatic and control patient's throat. Fungi other than Candida were cultivated from the throat in 15% of asthmatic children and 3% of controls. In secrets from the lower respiratory tract gained by bronchoscopy, laryngoscopy, or through tracheostomy there were moulds in 34% among the asthmatics and in 15% of the other cases. Allergic respiratory tract diseases facilitate the harbouring of moulds in the respiratory tract but do not influence the presence of Candida albicans. Moulds could often be cultivated even in patient not allergic to them. However there are chronic cases caused by immun reaction to the moulds in the patients' respiratory tract. Microscopic detection of budding and branching, myceliform fungi in the secret produced by coughing supports the diagnosis of mould causing chronic asthmoid bronchitis. New peroral broad spectrum antimycotics facilitate the treatment of such cases. The authors succesfully treated some patients with Clotrimazol (Canesten, Bayer) and all cases responded well to 5-Fluorocytosan (Ancotyl, Roche).