A breathing device for intra-oral use particularly useful to increase the air flow through the nares, the nasal passages, pharynx, and larynx of a user includes a generally U-shaped member curved in an arch to conform to a users upper dentition, edentulous maxillary ridges, or any prosthetic device. The U-shaped member is provided with at least one wall having a depth slightly greater than the vertical dimension of a users upper dentition and a receptacle to receive the upper dentition, edentulous ridge, or prosthetic device. A pair of nasal passage expansion members is disposed along opposed sides of the U-shaped member and are positioned to extend into the muco-buccal and muco-labial vestibule of a user distally from the lateral extent of the nares to the zygoma whereby upon insertion of the breathing device into the mouth of a user, the walls of the muco-buccal and muco-labial vestibule engage the muscles of facial expression thereby enlarging the nares and nasal passages of a user resulting in an increase of air flow and air velocity into the nasal passages, pharynx, larynx and respiratory system.
