There is no fastest way to expel phlegm, but some non-pharmacological measures can help to expel phlegm, such as back percussion, postural drainage, and drinking plenty of water, etc. In addition, medication and other medical interventions should not be ignored. 1. Knocking on the back: Knocking on the back can help to expel phlegm through vibration and other physical principles, which can lead to phlegm drainage into the large airways. 2. Extracorporeal drainage: For example, patients with right-sided lung lesions can be positioned in the left lateral position for postural drainage, which may also be helpful for phlegm expulsion. 3. Drinking more water: when drinking too little water, the phlegm will become more sticky and not easy to cough up, drinking more water is also helpful for the expulsion of phlegm. In addition, for patients with coughing phlegm, it is also necessary to use phlegm remedies such as aminobromine hydrochloride, carbocysteine, etc., and give the appropriate medication for the cause of the disease, and even some patients need to take suction and bronchoscopy and other related treatments. If the patient coughs up sputum or combines with other respiratory symptoms such as cough and chest tightness, it is recommended to consult a doctor in time for standardized treatment under the guidance of the doctor.