Many patients sometimes bring out phlegm when coughing, in fact, there are some benefits of having phlegm, because phlegm can expel dust and bacteria from the respiratory tract, so that the respiratory tract remains smooth and healthy, and prevent harmful substances from invading the lungs and causing infections. If patients want to reduce phlegm, they can use the following methods: 1, take expectorant drugs to promote phlegm discharge. 2, drink more water. Water can serve the purpose of diluting phlegm.3. If bacterial infection causes yellow phlegm, medication can take some antibiotics, such as amoxicillin to relieve the infection and relieve cough symptoms.