Novel compositions consisting of semi-interpenetrating network of cross-linked water soluble derivatives of basic polysaccharides and a non-cross-linked component, which is an anionic polysaccharide are provided. Methods for the production of such compositions are also disclosed. Preferably the basic polysaccharide is chitosan or a derivative thereof and the anionic polysaccharide is hyaluronic acid. The compositions can be formed into gels or films, for example, and thus find use in a wide range of medical applications in the fields of dermatology, plastic surgery, urology and orthopaedics.
