In a process for the preparation of an article having a contact biocidal property, there is provided a polymer solution which contains atomic/metallic silver in suspension or complexed with the polymer and/or which contains a silver compound in solution, in suspension or complexed with the polymer. This polymer solution is applied to a substrate by impregnation or surface deposition, thus coating the substrate. Alternatively, it is possible to convert the polymer solution to a fibre, film, powder or foam, effectively forming the article from the polymer solution instead of coating an existing article. In either case, any silver compound present is reduced to atomic/metallic silver, and the resultant article is dried.Chitosan is preferably used as the polymer, although poly(vinyl alcohol) and sodium alginate can also be used. The polymer may be cross-linked at a suitable point in the process to insolubilize it.