Hua Gai San is often used in the following formula: “Hua Gai, hemp, apricot, Chen Sang Pi, Su Zi, red poria, roasted licorice, the lungs feel wind-cold and the qi is not propagated, coughing and wheezing with sound and phlegm is unfavorable”. Hua Gai San is recorded in “Bo Ji Fang”, which is composed of Su Zi, Red Poria, Sang Bai Pi, Chen Pi, Fried Almonds, Ephedra and Roasted Glycyrrhiza, it has the efficacy of declaring the lungs and resolving the phlegm, relieving cough and calming asthma (stopping coughing, calming wheezing), it is used for treating lungs affected by cold, coughing, phlegm and unfavorable, fullness in the chest and diaphragm, constriction of the back and neck (because of the spasm of body due to the feeling of wind-cold and convulsions), heavy voice and nasal congestion, and vertigo and other dizziness. In this formula, ephedra has the efficacy of sweating and dispersing cold, promoting the lungs and resolving phlegm; almonds and suzi have the efficacy of lowering qi and eliminating phlegm, promoting the lungs and relieving cough; Chen Pi can regulate qi and dry dampness; Sang Bai Pi can diarrhea the lungs and induce diuresis; Poria cocos is capable of seeping dampness and promoting water movement; and baking licorice can harmonize all the medicines to promote the lungs and resolve phlegm and relieve coughing and wheezing. The adverse effects and contraindications of this formula are not clear. It is recommended to treat the symptoms under the guidance of a doctor, and to follow the doctor’s instructions, not self-medication.