The current invention pertains to methods of clearing mucus from airways of patients using devices for applying high frequency oscillations to the air passing through the airways of the patients. The devices can comprise a mouthpiece and a high frequency oscillator operably connected to the mouthpiece. The devices create turbulence throughout the airways of the patient from the mouth to the alveoli when the patient breathes through the mouthpiece, thereby clearing the mucus from the airways and helping the patient breathe easily. In certain embodiments, the device is a portable device. In further embodiments, the device is battery operated. In further embodiments, mucus cleared from the airways of patients and/or exhaled breath samples from the patients are collected for analysis and diagnosis during and/or following application of high frequency oscillations.
