The present invention provides a method for delivering a substance to the nasal cavity of a subject in which drawing air from a mouthpiece triggers release of a substance to a subjects nasal cavities. The device comprises a container for containing the substance in fluid communication with a nosepiece, a valve with an active configuration and an inactive configuration, and a trigger mechanism to reconfigure the valve from its inactive configuration to its active configuration and vice versa. Drawing air from the mouthpiece, e.g., when the subject takes in air by mouth, activates the trigger mechanism, thereby reconfiguring the valve from its inactive configuration to its active configuration for a predetermined period of time and delivering the substance from the device to a nasal cavity of the subject.
