Phlegm fire refers to the disease of invisible fire and visible phlegm that are boiled and glued together and stored in the lungs, the so-called "phlegm in the nest". Usually there may be no obvious symptoms, but it may be triggered by external evil or internal injury caused by diet. Its symptoms are quite similar to asthma, with fever, chest pain, dry mouth and lips, and phlegm that is difficult to cough up. It is a symptom of phlegm nuclei on the head and behind the ears like beads, or tuberculosis under the internal organs. The nuclei are tight when pressed and cannot be moved when pushed, and there are also red tongue with yellow fur, stringy and slippery pulse, etc. It is named because it is caused by liver fire and phlegm depression.