A hydrophilic resin based on cross-linked polyvinyl alcohol and containing appropriate aromatic moieties, suitable for mercuration, was prepared. Such supports were then treated with mercuric salts to obtain hydrophilic materials which showed a high affinity towards thiols and thiol-containing proteins like bovine serum albumin and bovine liver catalase. Some properties of both the mercurated resin and an immobilised catalase preparation were studied.