The present invention relates to a method for the reduction of the formaldehyde emission of wood-base materials by application of nitrogen-containing compounds, wherein (i) a mixture which comprises at least one polyamine and, if appropriate, up to 20% by weight, based on the mixture, of urea is applied to the wood-base material; (ii) polyamine is applied on or in the particle or fiber cake; (iii) polyamine is applied to the coating substrate used for surface finishing and/or (iv) polyamine is applied to the exposed areas; the polyamines having a molecular weight of at least 500 g/mol and at least 6 primary or secondary amino groups.