A polysaccharide-based solid material including, in its mass, at least one active agent having bactericidal, fungal, insecticidal and/or flame-retardant properties, and at least one complexing agent and/or at least one polymeric matrix having a complexing agent. The active agent includes at least one compound selected from the group including boron, silica, aluminum, phosphorus, iodine, derivatives thereof, aluminosilicate derivatives, and mixtures thereof. The solid material is characterized by an improved stability and by reduced environmental impact, and makes it possible to prepare materials based on wood particles and woods having a particular resistance against environmental attacks such as moisture.