ABSTRACT: OBJECTIVES:Postoperative bleeding and adhesion formation are the two most common complications after endoscopic sinus surgery (ESS). The former sometimes can be life threatening and the latter is the most common reason requiring revision surgery. This study was designed to evaluate the effect of newly developed chitosan gel (8% carboxymethyl chitosan, Surgi shield) on hemostasis and wound healing after ESS. METHODS:A prospective, randomized, double-blind controlled trial was conducted in 33 patients undergoing symmetric ESS. At the conclusion of the operation, Surgi shield was randomly applied on one side of the nasal cavity, with the opposite side acting as control and the bleeding quantity of the surgical field was evaluated every 2 minutes. And then, Merocel was placed in the ethmoidectomized areas of the both sides. Five milliliters of Surgi shield was applied to the Merocel of intervention side and saline was applied to the other side. Merocel in both nasal cavities was removed and 5 mL of Surgi shield was applied again to the intervention side on the second day after surgery. The nasal cavity was examined using a nasal endoscope and the degree of adhesion, crusting, mucosal edema, infection, and granulations were graded at 1, 2, and 4 weeks after surgery. RESULTS:Complete hemostasis was rapidly achieved in the Surgi shield applied side compared with the control side at 2, 4, 6, 8, and 10 minutes after application of Surgi shield (P=0.007, P=0.004, P<0.001, P=0.001, and P<0.001, respectively). There were significantly less adhesions on the Surgi shield applied side at postoperative 1, 2, and 4 weeks (P=0.001, P<0.001, and P<0.001, respectively). The degree of mucosal edema, infection, crusting, or granulation formation assessed by the endoscopic features in the Surgi shield applied side was not significantly different from that of the control side (P>0.05). No adverse effects were noted in the patient series. CONCLUSION:Surgi shield containing chitosan can be used safely to achieve rapid hemostasis immediately after ESS and to prevent adhesion formation.