Pharyngocutaneous fistula is one of the fatal complications occurring after head and neck reconstruction with neck node dissection. Even minor salivary leakage from the fistula could cause serious infection and threaten the viability of the transferred flap or even lead to the rupture of jugular vein. In such cases, proper management is difficult, and the chances for recurrence rise. We used a collagen patch (TachoComb) for fistula prevention and treatment. TachoComb, a collagen patch integrated with activated thrombin and fibrinogen, was used to prevent postoperative fistula formation in the initial reconstruction by applying them on sites with a high risk of salivary leakage. The patch was applied to 16 patients who had hypopharyngeal reconstruction, and the results were evaluated and compared with patients who had reconstruction without a collagen patch. A fistula occurred in 1 (6%) of 16 patients who received the collagen patch, whereas it occurred in 6 (14%) of 43 patients who underwent reconstruction without the collagen patch. In addition, the collagen patch was also used to treat postoperative fistula in 2 patients, and the results were successful after a single revision. Our results suggest that the collagen patch can be effective in the prevention and treatment of postoperative fistula after head and neck reconstruction, especially pharynx and cervical esophagus.