Abstract: The invention relates to medical technology, and more particularly to a device for the conservative treatment of nasal and paranasal sinus diseases. The present device comprises obturators for the posterior and anterior nasal openings, each obturator being in the form of an expandable sheath made of a resilient material and provided with a feed tube. The distal end of the tube is in communication with the cavity below the sheath, and the proximal end is provided with an adapter having a valve mechanism. The obturator sheath for the posterior nasal opening is hermetically fastened to the distal portion of its feed tube. The obturator sheath for the anterior nasal opening is hermetically fastened to a cuff. The cuff is provided with two channels, one of which holds the feed tube of the obturator sheath for the posterior nasal opening in such a way that the cuff can move along the entire length of the feed tube.