A medical barrier includes a sheet of unsintered substantially unexpanded hydrophilic polytetraflouroethylene (PTFE) polymer material having a density in a range of about 1.2 gm/cc to about 2.3 gm/cc, and preferably in the range of about 1.45 gm/cc to about 1.55 gm/cc, and having at least one textured surface. In accordance with one embodiment, the sheet has one textured surface and one substantially smooth surface, and has substantially uniform strength in all directions.