OBJECTIVE: The authors, thanks to experience obtained in a Unit for the treatment of digestive fistulas, discuss the possibility of a conservative treatment for the anastomotic fistulas. MATERIAL AND METHODS: From 2000 to 2003 were treated thirty-five patients with post-anastomotic gastroenteric fistulas marked according to their localization, way end output (51.5% high, 42.8% moderate and 5.7% low). The treatment is based on an aspiration system, sometimes integrated with an irrigation system. A semi-permeable barrier was created over the fistula by vacuum packing a synthetic, hydrophobic, polymer covered with a self-adherent surgical sheet. This system creates a vacuum chamber equipped with a subatmospheric pressures between 262.2 and 337.5 mmHg (350-450 mmbar), integrated with a continuous irrigation using antibiotic solutions or 3% lactic acid. RESULTS: The AA. obtained the resolution in 30 patients (85.7%), 3 patients needs the surgery (8.6%), 2 died, one for sepsis and the other one for malnutrition. The mean time for the closure was 45 days (from 20 to 90). A part of digestive external fistulas goes to spontaneous resolution so comes the idea that the creation of particular condition is the basis of their closure.