Dampness in buildings is believed to increase asthma and allergy risks. Studies have shown that the risk of asthma, allergic rhinitis, and atopic dermatitis is higher in damp homes. This is partly because dampness encourages proliferation of micro-organisms such as moulds, bacteria and mites, some of which are well established and documented toxin producers or allergens. Dampness in homes and workplaces should therefore be controlled in order to reduce the risk of occupants developing respiratory problems.