An object of the present invention is to provide ananti-adhesion membrane that has no toxicity to a livingbody, has flexibility allowing itself to fit an affectedpart as a hydrated gel, is uniformly crosslinked, and isimmediately absorbed in a living body after maintaining itsshape in the living body for a certain period of time.The present invention provides anti-adhesionmaterial, which comprises a thermally crosslinked gelatinfilm, and has a water content of 60 to 85% calculated bythe following formula (1):water content (%) = [(Ws-Wd)/Ws] × 100(%) (1),in the formula (1), Ws representing a weight (wet weight)of the anti-adhesion material immersed in a phosphatebuffered saline solution at a temperature of 25°C for onehour, and Wd representing a weight (dry weight) of theanti-adhesion material dried completely using a vacuumdrying apparatus.
