Abstract: An apparatus for assisting in the clearing of secretion from the lungs of a patient utilizes sonic pressure waves applied to the chest by an appropriate sound-generating transducer. A control unit allows the generation of a plurality of electrical signals at separate audio frequencies, which signals are combined and intermixed and amplified for driving the transducer. In general, the frequencies are in the range of 100-300 hz. A first frequency is chosen to coagulate the lung secretions, while the application of subsequent frequency signals breaks the secretions and facilitates their migration from the lungs. The use of sonic pressure waves minimizes trauma to the patient.