The incorporation of nanosized metal particles into cyclodextrin-containing material leads to a "reactive" barrier material having excellent barrier properties. Also, it has been found that the presence of nanosized metal or metal alloy particles in a barrier material such as thermoplastic material, wherein said material comprises cyclodextrin derivatives, may be advantageous in achieving excellent barrier properties. The barrier material of the present invention may provide improved barrier resistance to a variety of permeants and/or impurities. The diffusion of volatile substances through the barrier material may be prevented by adding compatible derivatized cyclodextrin and nanosized metal particles to the material used. Accordingly, the inventive material also is suitable for many applications including food-contact packaging, flexible packaging to dispose of adult and baby diapers, incontinent products, hospital and household waste and also for packaging pharmaceutical products, medical devices and dental materials.