It is intended to provide an adhesion preventive by which the adhesion of the surface of an organ can be effectively prevented and which is absorbed in the body, has a high safety, can be easily produced and, therefore, is highly useful in practice； and a method of preventing adhesion by using this adhesion preventive. Namely, (1) an adhesion preventive containing a water-absorbing crosslinked γ-polyglutamic acid compound as the active ingredient； (2) the adhesion preventive as described above wherein the water-absorbing crosslinked γ-polyglutamic acid compound is in the form of a powder having a water absorption rate of from 800 to 2000； (3) a method of preventing the adhesion of an organ characterized by bringing the adhesion preventive as described above into contact with the topical organ surface； and (4) the method of preventing adhesion as described above wherein the topical organ surface is in the moist state.
