A device that delivers nitric oxide containing gas as a therapeutic agent for treatment of upper respiratory tract infections by confining said therapeutic agent to the upper respiratory tract, where the upper respiratory tract includes the nasal cavities, sinuses, and nasopharynx, said device comprising: a resistive element (2) configured to cause closure of the solft palate (1) of a mammal during an exhalation cycle thereby sealing the nasopharynx from the lower respiratory system (9)； and a flow-control valve connectible to a nostril of the mammal and a nitric oxide gas source (3), said valve configured to open during the exhalation cycle thereby causing flow of said nitric oxide gas into the upper respiratory tract.
