Provided is a biocompatible polymeric composition comprising 1) one or more polyanionic polymers, such as alginates or hyaluronates, and 2) one or more polycationic polymers, such as chitosan or DEAE-Dextran. The composition may be useful in the treatment of wounds as the polymers cross link in situ in a wound forming a gel. In a preferred embodiment the composition consists of 0.1 to 5% by weight of sodium alginate, 2 to 25% by weight of chitosan, and water as a solvent.