OBJECTIVE To evaluate the ability of the two currently available surgical barriers, oxidized regenerated cellulose and expanded-polytetrafluoroethylene (PTFE), to prevent postsurgical adhesions. METHODS Murine uterine horns were approximated in the midline and the contacting uterine surfaces injured by electrocautery, cutting, and scratching, with and without barriers interposed. Sham-operated and experimental animals had adhesions assessed visually and histologically 7 days postoperatively. In another group, adhesions were created and then lysed 7 days later with barriers interposed. Readhesion formation was assessed 14 days after lysis with the PTFE being removed 7 days after lysis. METHODS Research laboratory RESULTS Adhesions occurred at 58.5% of the electrocautery sites without barriers, 100% of the readhesion sites with recautery for hemostasis, and 92% of the recautery sites without hemostasis. None of the sham-operated sites developed adhesions. When oxidized regenerated cellulose was interposed, adhesions were observed at 36% of uninjured uterine horn sites, 62% with single and 92% with double electrocautery injuries and 90% of the reformation sites. The PTFE did not cause adhesions in uninjured controls and completely prevented adhesion formation and reformation, regardless of the type of injury or whether hemostasis was achieved. A thin cellular membrane, continuous with the uterine serosa, enveloped the PTFE. CONCLUSIONS Expanded-polytetrafluoroethylene, but not oxidized regenerated cellulose, prevents adhesion formation and reformation in this murine uterine horn model. Additionally, oxidized regenerated cellulose was adhesiogenic even without surgical injury.