The paper presents an evaluation attempt af Mucosolvan in the upper respiratory tract diseases. A group of 50 patients underwent observation. They were hospitalized in our Department due to acute and chronic inflammations of respiratory tract, malignant tumours and larynx, and trachea stenosis. In cases of larynx and trachea stenosis there occur disturbances in the cleaning of surface of mucosa. Normally, it is done by means of mucociliary system. In the modern postoperative therapy mucolitic preparations are very useful.