Since Fleming had discovered the lysozyme and had applied the anti-inflammatory enzyme clinically, authors have used the hydrolytic enzyme of mucopolysaccharide lyxozyme on the chronic maxillary sinusitis. It's pharmacological effects are bacteriostatic and anti-inflammatory actions, inhibition of bleeding and hydrolysis of mucopurulent discharge, reconstruction of ciliary activity and synergistic action of antibiotics. The therapeutic purpose of the paranasal sinus disease is the hydrolysis of mucopurulent secretion which is enabled to improve edematous swelling of nasal mucous membrane, and to activate the ciliary movement of paranasal sinuses. In the present report the author studied on the therapeutic effects of the lysozyme (Neuzym) per oral on the 30 cases of the chronic maxillary sinusitis and the following results were obtained. 1) The Neuzym must be given to rather light inflammation selectively. 2) The effects of Neuzym appeared relatively early within ten days after beginning of the treatment. But the improvement in X-Ray appeared after 3 weeks. 3) The clinical improvement (subjective symptoms and rhinoscopic findings) of the 30 trial cases were excellent in 30%, good in 43.3% and poor in 26.6%, respectively. The overall improvement was 73.3% of 30 cases. 4) The improvement in X-Ray findings were excellent in 16.7% and good in 20%, respectively, and 63.3% of the 30 cases failed to show any improvement.