A device and method for loosening mucous secretions from a subjects lungs including a vest-like garment having enclosures thereon, the enclosures containing one or more sonic transducers, the output face of which is arranged to face the subject's body, the sonic transducers configured to repeatedly emit sonic bursts having a duration of about 10 to about 50 milliseconds at one or more frequencies ranging from 100 Hz-400 Hz, at a rate of about one to about four bursts per second.