Moisture damages of buildings increase respiratory symptoms and the risk of development of new cases of asthma. Scientific evidence of possible other health effects of moisture damages is scanty but they cause plenty of concern. The management of indoor air problems is further hampered by the lack of health-based limit values. Patients having symptoms from indoor air present a challenge to the doctor, because our ability to apply scientific data to an individual building or patient is very limited Although the factors increasing asthma and respiratory symptoms in buildings with moisture damage are not known in detail, every attempt should be made to prevent and correct the moisture damages.