Abstract: A method of delivering a substance in aerosol or powder form to the upper respiratory tract is provided. The substance is orally administered into the larynx, through the pharynx, and out from the nose while minimizing inhalation into the lungs, whereby deposition of particles in the upper respiratory tract is achieved with limited deposition in the trachea, lower airways and lungs. Also provided is an oral delivery device having a mouthpiece for oral inhalation of a flow of a substance into the upper respiratory tract and a flow restrictor for enabling arrestment of the flow minimizing inhalation into the trachea, lower airways and lungs, which provides for a deposition of particles in the upper respiratory tract with limited deposition in the trachea, lower airways and lungs. Also provided is an oral delivery device having a mouthpiece for admission of a flow of a substance into the upper respiratory tract and a flow generator for pressuring the substance into travel through the upper respiratory tract.