Introduction:
Moulds are the one of the known biological factors that have a negative impact on human health. Moulds are commonly present in residential and work environments. Materials plentiful in organic compounds, such as building materials or paints, are a splendid substrate for the development of moulds. The first documented mention of a study describing the harmful effects caused by moulds in buildings emerged in the early nineteenth century. In Copenhagen and then in Padua, moulds of the genus Penicillium, Cladosporium and Mucor were found in buildings.

Objective:
To present the current state of the allergic properties and other negative health effects caused by moulds isolated from buildings.

Brief description of the state of knowledge:
The literature and own research clearly shows that moulds and their secondary metabolites can evoke toxic effects on human and animal health, and cause symptoms similar to allergic diseases. These allergens have been noted in spores as well as other fungal fragments; however, most allergens are located in germinating spores, in the hyphal tips and in mycelia. Fungal allergy can express in different ways: asthma, rhinitis, conjunctivitis, urticaria and atopic dermatitis. Fungal allergy antigen is bound to IgE-dependent reactions but also to reactions independent of IgE.

Conclusions:
Moulds are a significant but difficult to detect etiologic agent of different allergic diseases. Prevention of this diseases is important for patients with suspected connection between common allergic symptoms and affinity with moulds.